Watch (follow) a fact type
It is interesting to watch a fact type and get notifications when top user is changed in the context of that fact type.
For example, it was known that Marat pressed 100kg, but it was interesting that there is a new person who pressed 140 kg (of course if I am interesting in pressing). I would like to get somehow a notification (on the website) that in that group (who is pressing) we've got a new records-man.
Alex Yakunin commented
Nice idea ;)