Something that we've wanted to do on TA for some time is the ability to comment on items in your friend feed. So when one of your buddies wins a particularly hard achievement, completes a game, sets a goal etc, you can comment on it and (s)he'll be able to see that in their feed, and comment on your comment if they want to.
This is something I've been working on for a while, and I've just put version 1 of the code live (which explains the odd outage).
As you will see, the tabs have gone from the feed and there are a lot more items in it.
At the moment, you will be emailed if one of your friends comments on your items, but tomorrow I will add a setting to switch that off.
I've done a whole lot of other stuff as well, so have a look in the Forum forum for more info.
I've also completely re-written the inbox code so it should be much faster, and every single page has been rewritten in some way, to try to speed everything up.
I've also fixed the My Settings page so you should be able to update your settings now.
There could be a few bugs (the Breadcrumbs aren't working for instance), but I will get them all fixed in the next 24 hours (if I do another update now everyone will go mental - the site dies for 5 minutes every time the code updates).