tinyurl.com

TinyURL.com is a very cool but very simple service. It will convert long urls to short ones. For example it converts:

http://yp.yahoo.com/py/ypMap.py?Pyt=Typ&tuid=12005015&ck=1714580355&tab
=B2C&ycat=7737307&city=Campbell&state=CA&zip=95008-6739&uzip=95008&
country=us&msa=7400&cs=9&ed=ikFr96160SzGYWtylOsVBXZXaPZpM4dNUHjWP
jcMNiyWiuaGa1E_xJbAINlV3LyR4ThZXFhM&stat=:pos:0:regular:regT:1:fbT:19

to:

http://tinyurl.com/475rl

Right now the service is free, but I could see themputting ads into it. For example, when clicking on one of the tinyurl.com links, it could put the linked content into a frame, with ads around it.