Just about everyone uses Twitter (or one of it’s clones) these days and that number is increasing exponentially everyday. Since services like Twitter limit each message to 140 characters, shortening URL’s that sometimes are at least 140 characters is an absolute necessity.
Let’s take a look at an example. The url below is 111 characters. That’s pretty long and only leaves you 29 additional characters to type in your Tweet.
http://remove-malware.com/antimalware/anti-malware-howto/malvertising-on-the-rise-how-you-can-protect-your-pcs/
Now, let’s use one of the most popular URL shorteners called Bit.ly to shorten this really long URL to….
http://bit.ly/a3cOyu
Wow, what a difference! From 111 characters down to 20. Now there’s a lot of room for actually writing something. Awesome service right? 
Yup, except when a malware distributor bit.ly’s a malicious URL and then posts it on Twitter (keep in mind Twitter is searchable). A typical Twitter user has no idea where that actual Bit.ly URL goes to. Here are a few stats to consider:
- about 1 in 1000 shortened URL’s lead to malware
- 26% of tweets contain a shortened URL
Have no fear…Bit.ly is here…with their very own firefox plugin that exposes the real Bit.ly destination link.
After you install the addon in firefox head on over to Twitter to see how it works. When you mouse over a Bit.ly URL you get a nice little window 
showing you the destination URL, how many times it’s been clicked and in the bottom right hand corner a bit.ly link that gives you more details on the URL in question.
Other Twitter applications like Tweetie and Tweetdeck already include the capability to expose shortened URL destination links.
