* Built-in blog posting. Instead of having to laboriously log in to your blog every time you want to write a rant, you can just click a button in Flock's toolbar. It automatically detected the settings for our Typepad blog first time, and worked well - although we couldn't add images and select categories.
* Search history. A simple touch this, but a mighty useful one. As well as using the top-right search box to rifle through Google, Yahoo and the like, you can also use it to search your site history. Now why don't IE and Safari have that?
* Online bookmark sharing. Flock links up with Del.icio.us, meaning that every time you add a bookmark it gets put online for anyone on the web to see. It's also handy if you work on more than one computer - you can just access the same set of bookmarks on whatever machine you're using.
Official Website: http://www.flock.com/
Developer's preview is available to download!