Should I use XML for this?

[Rockonmetal]

I am making one of those social networking sites like myspace and facebook. It will have gadgets like apps and stuff. Now I'm trying to decide whether the news feed and comments should be stored in a database or in an xml file. The only info that would be stored in the xml file would be the following: the user id, user account type (band/fan/musician), comment, time, and date.

Opinions?

[Twey]

'Some people, when confronted with a problem, think "I know! I'll use XML!" They then have two problems.'

No, static files of any format should never be used to store rapidly-changing data. You may wish to provide a function to export comments to an Atom feed, however.

[Rockonmetal]

what is an Atom Feed?