I signed up a Twitter account yesterday, because I want to record some tiny things in my life. I was thinking to write a web application for myself, but Twitter has done a great job for what I need. It also have a Facebook Application, however now I am using a add-on of Firefox called TwitterFox. Twitter’s Fackbook application is the first one application I manually added to my Facebook account, and that makes me understanding why Facebook can be popular. Most of web API are completely for outside usage. But Facebook’s API can allow outside programs are embedded into Facebook in UI and data.