Publishers are having a hard time making money. They seem to have decided that reducing their costs is not feasible, so the only alternatives are to try to earn more revenues or to go out of business. They've tried raising the price of new games, paid DLC, and in-game ads, but that still isn't putting them in the black, so now they're trying to get a slice of used game sales.

Somehow I don't think this'll put them over the top, either.

I'm gonna rent it since I'm a big MMA fan but I don't think I'll bother paying $5 for the online multiplayer code. Online multiplayer just isn't that enjoyable for me. Full of annoying assholes who quit during matches or act disruptively (swearing, poor sportsmanship, homophobic and racial slurs, etc.)

It amazes me how many gamers on the internet support the crusade against the second hand and rental market. If you've ever sold/traded-in one of your videogames before, you have no right to bash used sales. Because you yourself have contributed to that industry when you sold your games. How many people buy all of their games brand new and never sell their videogames? If that's what you want to do, fine (nothing wrong with being a collector), but don't push your way of doing things on the gaming majority. Videogame resale (ebay, amazon, gamestop, whatever), trade-ins, rentals, etc. are here to stay.

Can't wait to see what kinds of reactions there are when it finally happens.

From what I recall, they said they were considering a subscription based system back in February and they already have the $15 map packs for Modern Warfare 2. 

With Battlefield: Bad Company 2, it costs $15 to get the VIP code and I also noticed that specializations are for sale at $2 each.