UPDATE: Extension no longer working. The page that it uses to get the data is gone. I'll have to rewrite the extension to use the API or scrape the new global inbox.
I made a notification extension for Chrome:
It summarises all your Stack Exchange recent activity pages showing:
- Current Reputation
- Reputation change
- Moderator messages
- Responses
- Revisions (edits to your posts)
- New badges earned
To add a site go to your Recent Activity page (click on the Envelope at the top of the pate) and a link to add it should appear in the popup.
Note: It was initially made for Stack Overflow, Super User, etc. so it tests for accounts on those sites by default, but if you don't have accounts on them it won't add them to the popup. If you have accounts on them you don't want to appear you can remove them on the options page.
/users/recent/page seems to have been removed... – Isaac Apr 5 '11 at 12:02