Matchmaking in older installments of the Call of Duty series on Xbox 360 seems to be working again and attracting many players.
Anyone who plays older parts of Call of Duty with their Xbox 360 or gambles them via backwards compatibility only had limited fun online. Either no game came about or the matches were contaminated by cheaters.
Possibly spurred on by recent events surrounding the acquisition of Activision Blizzard, lobbies are now active and filling up quickly, and matchmaking is working again.
For example, Call of Duty: Modern Warfare 3 had over 7,000 active players on Xbox 360. In other older parts were even more than 76,000 and 123,000 players respectively turned off.
On the other hand, matchmaking should still not work on the PlayStation 3 and PC platforms.