If a player loses several games in a row on timeout, does the site lock their rating so all openents that win games after the time out have their rating adjusted based on the same rating rather than a rapidly plunging?  I only ask because it looks like that's whats happening with one of my opponents who has apparently been unable to play for several days. 

Just so you know, my game with him already ended and I don't care that much about ratings anyway.  I'm just curious.

No,  the winners only benefit from the new lower rating (rapidly plunging as you put it)

Not quite true.  That's how it used to be.  However, during the LB fiasco a couple of months ago, the staff changed it to what AZMatt is describing.

Edit: Make that 8 months ago.  One's perception of time sure does change after playing correspondence chess.....

omnipaul is correct. After a player times out of a few games, their rating is "floored" meaning that it will not plunge into infinity. This ensures that players who were near the timing out players rating during the time out, are not completely cheated out of their proper rating increases. BUT, if they come back, their Rating Deviation is also changed so that they will have a harder time getting back whatever rating they did lose.

Thanks to all of you for satisfying my curiosity.  I think that's a very fair policy.  And not because it helped my rating in any way - I was one of the first of his timeouts so it wouldn't have mattered in my case. 

By the way, who is LB?

If i understood well the rating don't change for his oponents, but changes for the timeouted...

Also a fair policy.

This was back in the days when signing up for a thousand games simultaneously on chess.com was thought to be a lot.  http://www.chess.com/forum/view/community/upper-limit-on-games-playing-concurrently