I spent part of this morning having a go with the new Facebook app from the folks at WordPress.com (a Webware 100 winner). Once installed and linked up with your Wordpress.com account, you can post to any of your blogs without leaving Facebook. You can also check traffic stats and add bookmarks to your blogroll. The actual blog authoring tool is very limited in this release. There's no way to add links or pictures to posts. You're also unable to manage some of the subtleties of authoring like bold and italicized fonts, indentations, and the handy spell-checker. In other words, don't expect any of the nice, fancy WYSIWYG tools you get when blogging via Wordpress.com
The killer app here is the social tie-in with your feed and friends. For example, every time you post something on your blog, be it in the Facebook application or in Wordpress.com, it will show up on your news feed for all to see. Previously, the only way to call attention to one of your posts was to go writing it on people's walls, or noting it using Facebook's share feature. This automates the sharing feature, so you don't have to do a thing.
The other really neat feature is how the application links you up to the blogs of your Facebook friends. You can browse their WordPress.com blog posts without leaving the Facebook app or visiting the source blogs. The only requirement is that your friends have the WordPress Facebook app installed too.
Still missing is a way to use this app with hosted WordPress blogs, a feature which will likely be added in a future update.