Not all URL shorteners are created equal, especially if you’re shortening URLs for work.

What good is it to shorten a link if it doesn’t work for end users? That will deprive you of page views and frustrate users (potentially losing customers). Speed and reliability matter.

Twitter and social media users know how important URL shorteners have become. Without URL shortening, Twitter and other microblogging services would be much less functional. Many journalists and news organizations are sharing links via Twitter, Facebook, MySpace and others. For these people and companies, URL shortening reliability is very important.

Royal Pingdom did a great study comparing the speed and reliability of URL shorntening services. Key findings:

• Ow.ly had 0 downtime between July 16 and August 16 of 2009. That’s amazing. Bit.ly was close with 99.98 percent uptime. Tr.im came in last with a 99.10 percent uptime, which translates into almost 80 hours of downtime a year.
• Is.gd is the fastest URL shortening service, followed by Bit.ly and Ow.ly. Snipurl was the slowest.
• “Five out of nine services had a 99.9% uptime or better, which we have to consider acceptable.” There is a big difference in 99 and 99.9 percent uptime, especially when you’re trying to share links at peak times of day.
• When speed and reliability are combined, Bit.ly and Ow.ly tied for first. Tr.im came in last.