Forum Moderators: open
I'm sure the concept of showing who the most-recent poster in a thread in a list of threads is not a new idea but it seems like it would cut back on a lot of bandwidth useage as people wouldn't be checking threads they're interested in and have posted to to see if anyone replied.
A new idea (to me) is for the "recent posts" option. Allow users to select which forums they want to monitor for "recent posts" instead of all of them.