So I had this thought, and I'm sure it's been done, I just haven't seen it around. Could you do single player games where the players are mostly doing their own stuff and having their own adventures and only occasionally meet up to do multiplayer missions? I'm thinking specifically for FFG's Star Wars RPG, if that makes any difference. I just kind of liked the idea and I thought it might present something new for players who want more things to do instead of waiting for other players to post for the story to progress.

Thoughts?

It's been done, and is done every now and again. I've tried it a couple of times in various settings and systems. The main problems I run into are 1. GM burn out. Every solo story is basically a separate game. You get three or four of those going on at once and a GM can get overwhelmed pretty quickly. And 2. time frames. PbP time frames are shifty and tricksy. Even a quick-posting combat seldom moves forward faster than a round a day. So for D&D that's 6 in-game seconds per 24 real-life hours. Meanwhile, an uneventful walk across the country can be summed up in 'Six months later....'

So it's really hard to keep everyone in the same reference frame, time-wise, so that meeting up makes any kind of sense.