Are Blacklisted Link Shorteners Getting Your Emails Blocked?

Have you ever used a link shortener on any of your email marketing campaigns?

They’re a handy way to send a long URL to someone using just a few characters. And while they’re nothing new (TinyURL turns 10 in January 2012), they’ve become particularly popular since the rise of Twitter, Facebook and other communication mediums where space is at a premium.

Chances are, you’ve looked at a long link in one of your emails and thought, “It’d be nice if that link weren’t quite so long,” and been tempted to use a link shortening service.

But did you know that link shorteners could potentially hurt your email deliverability rates?

How Link Shorteners Can Affect Deliverability

Link shorteners are handy for trimming down long URLs.

But in addition to offering that convenience, they perform one other function: they mask where a link actually goes.

This makes them appealing to spammers who either:

  • Don’t want recipients to see their actual website domains, or
  • Don’t want ISPs and other organizations to be able to filter out their spam by blocking emails that have the spammer’s domain in the body of the email.

Of course, some legitimate email marketers may find the idea of shortening links appealing, too. This is particularly true for those who send plain text emails, since in an HTML email you can simply link whatever text or image you want, as you would on a web page.

The potential problem happens when both a spammer and you use the same link shortener in your emails. If one or more ISPs start blocking emails that include that link shortening domain (to block the spammer), they may inadvertently block your emails, too.

So Which Link Shorteners Are Blacklisted?

I wanted to find out how much of a problem this could really be – after all, everything I’ve said above is true in theory, but I didn’t know how much (or if) it was actually happening – so I cracked open my browser, a spreadsheet and got to researching.

I checked 24 popular link shorteners against three popular URI blacklists:

These lists are used by some ISPs to determine whether an email should be placed in the inbox, bulk folder or neither. If the body of your email includes a link to a blacklisted domain, an ISP may choose to not deliver it to subscribers’ inboxes.

Before you look at the results below, keep in mind these results can change at any time. This data is as of June 23rd, 2011. A blacklisted domain could be delisted now, or tomorrow, and an unlisted domain could get listed at any time.

OK, with that said, here’s what I found. Results are ordered by Alexa Rank, starting with the most popular, bit.ly:

Link Shortener Alexa Rank Listed in DBL? Listed in SURBL? Listed in URIBL?
bit.ly 152 Yes No No
tinyurl.com 747 No No No
goo.gl 855 No No Whitelisted 1
ow.ly 1966 Yes No No
t.co 2403 No No No
su.pr 6539 Yes No No
budurl.com 6907 No No No
is.gd 8149 No No Whitelisted 1
lnk.co 10,250 Yes No Yes
fb.me 11,564 No No No
cli.gs 41,012 Yes No Yes
deck.ly 72,661 No No No
snipurl.com 73,378 No No No
tr.im 202,662 No No No
fur.ly 249,983 No No Yes
twurl.nl 307,728 No No Yes
u.nu 585,984 No No No
short.ie 695,684 Yes No No
blinky.me 1,108,121 No No No
kl.am 1,206,876 No No No
zi.ma 1,997,505 No No No
poprl.com 4,471,928 No No No
hex.io 5,784,912 No No No
ad.vu N/A No No No


Yes, I know Alexa rank isn’t a perfect measure of popularity, but Alexa had traffic stats on more of these link-shortening domains than Compete, Quantcast or anyone else I tried.

What Do These Listings Mean?

As you can see, none of the popular link shorteners were listed on SURBL as of June 23, 2011. A couple, goo.gl and is.gd, were actually whitelisted by URIBL.

However, eight of the link shorteners were listed in URIBL or the Spamhaus DBL. So if you sent out an email that included a link to one of those domains, your email delivery rate could have been affected.

Now, the point here is not “OK, so just avoid those ones that were listed.” To re-emphasize from before, these results don’t mean unlisted link shorteners will never cause problems. Any of them, even the ones currently whitelisted, could potentially be blacklisted in the future.

Here’s what you should take away from these findings:

  • Link shorteners are handy for trimming long URLs in tweets, Facebook statuses, and similar venues where space is at a premium. But space isn’t at the same premium in an email as it is on social media.
  • Whatever convenience link shorteners offer in an email is outweighed by the potential for those shortened links to hurt your email deliverability.
  • If you’re currently using these or other potentially abused link shorteners in your email marketing campaigns, stop!

Don’t Like Long Links In Your Emails? Here Are Some Options.

  • Set up your own link shortener. If you’re sufficiently tech-savvy, you can install a link-shortening script on a domain of your own. (You’ll need to come up with a short, available domain and register it.)Here are a few different options if you’re interested in this: YOURLS, Phurl.
  • Send emails with an HTML version instead of plain text-only emails. If you’re sending HTML email, all you need to do to not have long URLs appear in your emails is to link up appropriate text or images instead of just putting the full URL on display for subscribers.

One last note on links and emails: if you’re sending subscribers a link to a page on your website, isn’t it best for them to be able to see that’s where the link goes? If you see a shortened link in an email, don’t you pause and wonder where it’s going to take you? I sure do.

That’s why with AWeber’ email analytics you can track clicks using your own domain.

Sure, not all links in your emails go to your own website, but a lot of them do. Showing subscribers that they’re going to end up on your site may be the difference between someone clicking and not clicking.

Have You Used Link Shorteners In Your Email Marketing Campaigns?

If so, what was the reason? (I’m not being sarcastic; I really want to know, because I’m not seeing a reason. Enlighten me. 🙂 ) Have you seen any impact on clicks or email deliverability as a result of using them?

UPDATE: Steve at Word to the Wise has more on bit.ly blocking issues.


1. URIBL’s whitelist “contains legit domain names that [they] do not want to show up on any other URIBL lists.” More on their lists here.

65 Comments

  1. Lynn Brown

    7/31/2011 1:28 pm

    Thanks Justin for a very informative article about link shorteners. Something to certainly consider in all aspects of marketing. I like to use the anchor text in my emails and also ‘PrettyLink’ plugin works nicely for my blog, articles, etc.

    It really is too bad that we still have people that spend so much time trying to ‘buck’ the system and ruin it for everyone else. I mean, come on, social media marketing is providing such a huge platform for all of us to market properly and still make a an awesome living!

    When I started on the internet in 1995, I was learning from others then how to ‘spam’ people. We didn’t call it spam at first, we called it ’email farming’! So I was happy to see how we have evolved online to a more ‘social’ and transparent process. But others still seem to think by spamming and scamming and all that jazz, is going to make their lives better for that all mighty dollar.

    Build your community with solid connections, build relationships and your credibility will skyrocket. Visitors begin to trust you and then they will become a ‘long-time’ customer or client. YES, it really does work!

  2. Justin Premick

    8/1/2011 3:59 pm

    Hi Ben,

    I’d be curious to see what blacklist you were comparing that domain against. It’s not listed in any of the ones noted above, nor any other that I am aware of, and we haven’t noticed any such issues affecting customers as a whole. There are a lot of factors that can potentially impact delivery of a message to an individual, and it’s not necessarily one factor that results in a deliverability issue.

    Hi Lynn,

    I couldn’t agree with you more – trust and credibility are what email marketing is all about!

  3. Phil Steele

    10/6/2011 4:26 pm

    I had a disastrous experience with Goo.gl. Used it to shorten links in my Aweber email to 15,000 double-opt-in subscribers. Tested fine. Then when I actually mailed the message, Google disabled the link. I suppose they assume any large mail volume means spam?

    So immediately I have 15,000 angry subscribers telling me my link is broken. Thanks a lot Google!

    I had to re-mail my whole list with a new link, and it took days for the customer support issues to die down.

    I will never use Goo.gl again!

  4. Jude Banks

    11/1/2011 5:20 pm

    The information in the post and the comments is very useful, thanks.

    I wonder whether the same risk to delivery would apply when one uses tracking links?

    I don’t use url shorteners but I do use tracking links and I am noticing that the click through rates on normal links are a better than on the tracking links. I suppose it is a similar problem. People not seeing where the link will take them tends to discourage clicking.

    I don’t think it is a problem once you have trust and a relationship with your list, but for new subscribers where that has not yet been fully established, it could be an issue.

    Very helpful information. You’ve convinced me to use a domain or plugin instead!

  5. Kontorinventar

    11/3/2011 4:04 am

    Very good information, I didn know that shorteners cut get my email blocked, thank you for this information and have a nice day.
    Many regards from Denmark

  6. Justin Premick

    11/3/2011 7:39 am

    Hi Jude,

    There’s certainly something to be said for linking directly to your domain rather than redirecting your subscribers through a tracking domain.

    That’s one of the benefits of our email analytics tools: they can track email clicks to your website using your own domain (instead of a tracking one).

  7. Stephanie Everette

    2/6/2012 6:29 pm

    Thanks GREAT information. I do a lot a of email marketing and do use a short link when advertising.

    Thanks for the information it is very informative.

  8. Jim

    3/10/2012 10:33 am

    I’ve used them sometimes because I’m sending out text emails and a shortener prevents a link going over two lines, and it looks a lot nicer. I send emails worldwide, and so maybe a lot more of the people receiving my emails prefer text because of limited technology or expensive internet service.

  9. Ming

    3/11/2012 6:50 am

    What I normally do is to use a cloaked link in my domain so that I can increase the CRT and also cloak and track the link.

  10. Anthony

    5/15/2012 8:25 am

    Definitely not blacklisted…. yi.tl just launched: http://yi.tl

    yi.tl is the first URL shortener to offer support for category tags. This unique service allows users to group related URLs and easily retrieve old links. To save time, the site will even make tag suggestions based on the URL being shortened.

    Other features:
    – All links checked against Google’s Malware & Phishing databases
    – Detailed Preview pages
    – Full click through stats
    – QR codes provided for every URL
    – 19 character URLs (shorter than bit.ly and Tinyurl)
    – Reliable dedicated server
    – SEO-friendly 301 redirects

  11. Justin Premick

    5/16/2012 12:28 pm

    Hi Anthony,

    As I noted in the article, not all link shorteners are on the above URI blacklists at the time of this writing, but that even the ones that aren’t could potentially be:

    these results don’t mean unlisted link shorteners will never cause problems. Any of them, even the ones currently whitelisted, could potentially be blacklisted in the future.

    While link shorteners such as yours may not currently be on any URI blacklists, and may end up never being on them, it’s best to not use them for links in email marketing campaigns.

    Link shorteners are useful & have their place… that place just isn’t email.

  12. Scott

    11/21/2012 11:23 am

    A great post Justin that prompted lots of interesting discussion.

    I presume most of the responses here are Aweber clients that are trying to ‘get the message out’. Thought I’d respond with the ‘receiving end’ perspective of an IT manager trying to hold back the flood of material that is actually hostile (rather than your marketing, newsletters, etc.) Might be some useful context for all you folks trying to reach your clients.

    Trend 1 – well… long term reality, not trend. Today’s anti-virus software, spam filters, and miscellaneous other protection technologies are not fool-proof. So called ‘State-of-the art’ anti-virus catches about 95% of the viruses (think 1 in 20 undetected). The organized info-crime on the net is increasingly sophisticated and messing with your deliverability. Us IT folks are in an arms-race with the crooks and the crooks are better funded. Your messages are trying to co-exist with all this phishing, identity theft, etc.

    Trend 2 – Given Item 1, one of the big trends in the IT profession these days is supplementing all the security tech with phishing education campaigns to “street proof” our employees against current threats. Many organizations are actively training their users to be very skeptical and suspicious of the URLs they receive. (If you can’t actually tell where the URL goes, don’t touch it. The message came from acme.com but the URL goes to a different name? Don’t touch it. and so on…) See phishme.com for the sort of tools that are becoming commonplace.

    So there is nothing inherently wrong with URL shorteners but:

    1) Many of you have built your brand into something your clients trust. If you use a URL that’s not your own domain name, you are throwing away the benefits of the rep you worked so hard for.

    2) Like many things on the Internet, a few bad guys can ruin it for everyone. In the current security climate, clicking on a masked link (whether masking is the senders intent or not) is something people shouldn’t do – with a 10ft. pole wearing a hazmat suit… I LIKE short URLs but the unfortunate reality is that anyone in the habit of clicking on masked URLs or unknown domains is a victim waiting to happen.

    Trust is in short supply on the Internet. Use your own namespace. The IT guy

  13. Justin Premick

    11/21/2012 11:36 am

    Scott,

    Thanks so much for sharing your point of view as a receiver of email. You’re right to say that it’s easy to focus on the “get the message out” side of email campaigns and not think about the “process the incoming messages” side that sits between us and our subscribers.

    You make a great point about businesses needing to use their own assets rather than relying on someone else’s namespace and reputation. (This is part of why we enable clients to track clicks using their own domain, rather than forcing them to use a redirected tracking domain.)

    Thanks for lending us your insight and experience!

    (PS – your comment came through with some oddly encoded characters… mostly punctuation. I think I cleaned it up & replaced with what you intended, but sorry if any of it doesn’t reflect what you posted.)

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  15. RDub

    6/15/2014 12:23 pm

    Thanks for the heads up. I’m new to online marketing and haven’t as of yet built an email list. I do use link shorteners but only on my site for outbound links.