I can't describe it in the title very well, but bear with me. I used to rp a lot on Gaia Online, and over there, there was an option to roll a single die when you made a post. Having noticed there's a lot of 3.5 and PF games over here, I was thinking that having the ability to roll a die with your post would be really useful.
Basically, here's how it goes: You would hit a button saying you want to roll a die, then you select number of sides, add a positive or negative modifier, and then when you hit post, the site rolls the indicated die and does the math and puts the die roll as a header above your post. It's just an idea, of course, but I thought I'd throw something out there.