Safari 5.0.1 is out (check for updates on your Mac to get it) and it comes with official and overt support for extensions. So far, what I’ve installed is the Twitter extension, which is a bar that runs across the screen with a search field, something called “Related Tweets” and a button to Tweet, which takes you to the Twitter home page and prefills it with the URL you were looking at. One of the biggest features is a list of trending topics, which you might otherwise not look at. It doesn’t seem to notify you of new tweets on your timeline, though.

NY Times has another bar-style extension which lists the main headlines with small images.

These are both neat, though there’s a limit to how much you could easily pile on without dramatically shrinking the useful area of your browsers.

I’m using ScribeFire to write this – a blog client extension that basically opens up a page for you to write a post. Not bad so far, though it’s fairly simplistic.

Edit: ScribeFire did weird things to formatting. Had to fix in MarsEdit.