Now, I know there have already been a bajillion and one of these, but these are some new suggestions...
1) Subscribe to someone's blog, which alerts you when they write a new blog.
2) Reply to cmments, not just blogs.
3) Alert when someone replies to your blog/comment.
4) Latest friend activity [blogs posted, comments made, painting made].
5) Sending a message to all your friends [for when they don't wanna retype the same message over and over].
Hopefully this will be featured so that others may continue the list or HB replies on what's possible or in the process of being made.