SL-Mark: Speed ratings would be very useful. It would be especially useful if the speed ratings could be used to estimate the expected duration of a tournament. For my "Some like it fast" tournaments, I wouldn't care about the time control if I could specify that I only want players who are likely to allow completion within, say, six to ten weeks. Then I could set a 7-days time control to allow for Life's unexpected emergencies, safe in the knowledge that the usual course of events would be frequent moves by all concerned.

@Mélusine: Your concern wouldn't be as much of an issue as you might think. A fast player with occasional lapses is still a fast player, different from the once-a-weekers with their busy lives and in a different Universe to a crawler with hundreds of games.

For instance, if you play a game and the opponent is online and makes their move and it comes back to you, you might get to play the next turn. Someone with hundreds of games will never do that unless they are specifically giving priority to games with those who are online. Playing twice in one session would be very beneficial to you speed rating, having most games go to the end of a huge queue would be detrimental.