According to the official bit.ly blog, the link-shortening service is nearing 5 billion clicks per month. Helping matters is that Twitter replaced TinyURL with bit.ly as the default link shortener.
Why does this matter to Web professionals? Trust and familiarity. Short links are great but also mysterious. Think of it this way -- you're more likely to get a click on a link that consumers are used to seeing. It's like the difference between displaying a link to a .com and a .net, .org, .info or any of the other "unfamiliar" extensions.
Sign up with a professional bit.ly account and you can customize small links even more, such as including your brand or website name in the link. You will also receive deeper analytics.
And if there's a hotter trend on the Web than any other, it's video. Bit.ly has that covered as well, with bitly.tv -- a page showing the millions of Web videos being shared with bit.ly links. So I guess that's 5,000,000,001 reasons to use bit.ly.