An easy way to see when your comments have been replied to, and to read those replies, would be great. Reddit has this feature. Right now I'm unaware of any way to do this on LW besides checking each of the individual parent posts.
Yes it seems this is something that needs to be brought back, there is an issue for this that I raised a while back.
[Edit: Issues, Bugs, and Requested Features should be tracked at Google Code, not here -- matt, 2010-04-23]
Less Wrong is still under construction. Please post any bugs or issues with Less Wrong to this thread. Try to keep each comment thread a clean discussion of each bug or issue.
Requested features... sure, go ahead, but bear in mind we may not be able to implement for a while.