URL Shortening Services
URL Shortening Services exist because of the need to compress the length of a message to fit within Twitter’s 140 character limit. Some urls would exceed this limit all on their own, and thus to allow you to embed a long link in your Tweet, you visit one of these services and shorten the link down to about 20 characters or less. Bit.Ly is one of the better services because it uses 301 redirects to send people to the url site, thus also sending the linkjuice to the target site instead of to the shortening service’s site, and also because it maintains a database of stats on who clicked the link in your tweet, when and where.

