The bookmarklet opens a page on redirect.twitterland.net -- one of my servers. It grabs the referrer link and shoots it over to tr.im, with your tri.im username and password as params (also the apikey they gave me). It returns the shortened URL. I take the title of the page, add the shortened URL, and then redirect to twitter.com.
Every five minutes:
1. I check if there have been any updates to your twitter account.
2. I check back with tr.im to see how many hits your 100 more recent links have gotten and