Skeld |
Adventure Path Charter Subscriber; Pathfinder Starfinder Adventure Path Subscriber
This has been brought up numerous times in the past 7 or 8 years and Paizo's answer has always been that they don't like forum signatures (thats why we have customizable user profiles) and they aren't going to implement email notifications (because all that extra email looks like spam to ISPs). Paizo's also turned down the idea of custom avatars too, because they bring along whole new dimensions of potential problems.
Good luck!
-Skeld
PS: do a forum search and you'll find a graveyard full of threads on these subjects.