Personal Notes attached to Players
Having a way to put flags on potential players, notes-to-self on users, or something that can be used for a Player to keep track of other Players, which would only be readable by the Player that created the note, would be a great resource for collecting players and getting games together, or just keeping track of folks you've met along the way.
For instance, there is a player that lives in Plano, but he doesn't go online. I see that there are several players looking to game in his area and I'd like to pass on the info at the next meet. If I could flag those players I run across here online as a note-to-self "Plano Player", I could easily pass the word to our offline friend.
Another instance might be a GM that is ready and willing to run a sci-fi game, but you don't have time right now. However, you'd like to keep him in mind for when you get time to play. A custom "Sci-Fi Friday" note would be a great boon to you for just such an occasion.