Languish roleplayers: what features would you like to see in Play by Post?

[DontSayBanana]

I'm working on creating forum-like software with modules to facilitate playing pen 'n' paper RPGs over the Internet, and I was wondering what features you'd like to see in this?

Basically, I started with the idea that I want to play without having a million and one tabs open for dice rollers, character sheets, etc.  The obvious modules to include are stat tracking and a die roller, but I wonder what else you'd like to see?