Well, I don't use it much, so I don't see much difference in its usefulness.
You should! It's a great way to keep up with new posts, in combination with the Watchlist.I use Watchlist a lot!
The topics that are not on this list are because I haven't read them from the beginning. So that's why I don't use that button.
All the topics, even those that I haven't posted yet, but that I want to read, are on my list. (The list is already quite long.)
