URL shorteners, such as bit.ly and tinyurl, are services that help take longer URLs (which can be over a hundred characters long) and transform them into manageable links that almost never exceed 20 characters. URL shorteners are not new—TinyURL has been around since 2002. But their popularity has skyrocketed with the rise of Twitter, which only allows for 140 characters in any message.
So what could be so wrong with something so innocent?
From a technical standpoint, URL shortening services add another layer of indirection to an already creaky system. A regular hyperlink implicates a browser, its DNS resolver, the publisher's DNS server, and the publisher's website. With a shortening service, you're adding something that acts like a third DNS resolver, except one that is assembled out of unvetted PHP and MySQL, without benevolent oversight. In the ecosystem of a link, each party is harmed to some extent by URL shortening.
Let's face it, without a reverse lookup, that shortened URL could take you to all sorts of spammy places. Although early-adopters quickly found ways around this problem, late-adopters to microblogging find these strange URLs wolves in sheep's clothing.
It’s clear that URL shorteners will be around as long as micro-blogging (which shows no sign of slowing down. The challenge for the web community is to find ways to enjoy the benefits of URL shorteners while protecting against their downfalls.
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