Having just recently gotten into the blogger foray on a regular basis, I wasn't entirely familiar with URL shortening until now. I still don't totally get the concept, but I currently use bit.ly to shorten my links on Twitter (it's Twitter's default, but TwitterFeed lets you choose from a myriad of options). Bit.ly, probably the most recognized because it is Twitter's default service, is gaining quite a bit of company, however, as well as adding some services.
Bit.ly Pro is that provider's way of making "www" addresses a thing of the past. For instance, if you type nyti.ms into your browser, you will end up with the New York Times homepage. Other sites, such as The Onion, MSN, and the Wall Street Journal have also gotten into what is now the beta stage of bit.ly Pro, which also provides detailed statistics of use for those that sign up. Facebook has also entered the URL shortening mix, allowing users to either reach the Facebook homepage at fb.me, or utilizing Facebook's new username service by entering the username following a forward-slash.
URL shortening, albeit interesting, seems a little silly to me. Bookmarks became commonly used years ago, and users across the globe use them all the time to access their most frequented sites. Even if you are trying to attract new users, wouldn't it be easier to remember "newyorktimes.com" rather than "nyti.ms?"