Nearly all the main players in the browser world have their own blogs and while they might range in their usefulness they can give you an interesting perspective on the vendors ideas of themselves.
At Mozilla, Firefox is just a category, it’s not got it’s own blog. Recently it’s very focused on security and updates.
Chrome’s blog is really new, although there is an older blog for Chromium concentrated on performance and stability
Opera’s blog re-forces their position, unfortunately. The underdog’s blog is all about getting the word out from their tight following, the tech elements play second fiddle. The Opera developer area is great though …