I'd suggest to do a poll. In fact, introducing power creep by achievements you would have to do ingame is a pretty neat idea. Having in mind, to gain access to "exotic" stuff is currently only possible via SRP it forces you to spend and write a couple of hours only on forums for writing, designing, etc. Finding a way giving access to SRPs or special content combined with ingame(more special than "please deliver X commodity to Y) and forum work like Garret suggested might be pretty cool.