This isn't a solution for being over committed but it may help with keeping people involved.
We haven't started actual play yet, but I just started using an off forum application to kind of keep things up - specifically, I created a team on Slack and invited the players. Since it goes at the pace of IMing, it hopefully will help keep up the pace. Obviously this is contingent on players feeling comfortable giving out email addresses. I have the advantage of my players being my friends, so I already had their email addresses to send out the Slack invites.
We're still in char gen and Session Intro as the char gen for the game I'm running is pretty interactive, with a variety of side discussions as opposed to one main dialogue. I use Slack to
- let players know when different threads need input from a particular character to proceed, along with a link to that thread
- as a central repository for files (right now kept in Google Drive, put I will be pinning a picture web of PCs relationships, rules exerpts for char gen, and the blank character sheets)
Once the game starts, I plan to use it more for
- managing scenes where characters are in different locations and so monitoring different threads
- a place for side chatter/ooc stuff