I'm not much of a joiner but I grudgingly set up a Facebook page when I got several invites and I am still not convinced it is up to much. All the cool kids are doing it so why not me? Facebook is an open application platform (and if I were remotely technical this would really excite me), which enables a multitude of developers to build mini applications that Facebook users can 'load' to their page and use. These applications cover any number of uses and I have loaded one for books, questions and a travel application named 'where I've been'.
Here is my 'map':
According to the NYT the developer of this application is now $3.0mm richer via Trip Advisor. Trip Advisor is itself a fun site to browse if you are looking to find out what other travelers have said about airlines, hotels, destinations that you may be thinking about visiting. What they will do with this application is any one's guess. Perhaps I am cynical but the application as it exists is akin to notches on a bedstead - more bragging rights perhaps than anything useful.