Everyone wants to know why Xbox Live gold members have to pay for an online service and Sony customers get off scott free. I'm going to break it down for everyone. It's all about maintaining a service and the method of doing so. Both Sony and Microsoft take a different approach to supporting their online networks.
In general, developers are in love with Xbox Live simply because it's cost efficient for them. Every game released since Microsoft got into the console business that has or had downloadable content or online multiplayer is still connected to Live. Not only that but Microsoft ensures that they remain online. This means that games like Knights of the Old Republic still have their DLC available on Live today, and Crimson Skies: High Road to Revenge can be played online.
Developers are privileged enough to only pay a one-time installation fee, and Microsoft will maintain a videogame's servers and content as long as Xbox Live is online. Of course developers can also make their own adjustments as well. So instead of Capcom, EA, and Bungie paying to maintain their own servers; Gold subscribers are force to pay $50 a year to make up their expenses. The positive side is, developer aren't hesitant about putting DLC content on Live or including online options for the Xbox 360 games. In fact Square Enix has even considered applying some sort of online feature to Final Fantasy XIII on the 360
With that said, it's entirely the opposite for gamers owning a Playstation 3. You benefit with playing games online for free, but developers are forced to run their own servers since Sony doesn't do it for them. This is a reason why you don't see cross-voice chatting and what not on the PS3 simply because each server isn't co-dependent. The servers over at EA are certainly not connected to Activision-Blizzard as well. It's also less cost-efficient for developers which has them picking up the bandwidth-tab instead of Sony.
Much like Microsoft, the Japanese company charges developers a one-time installation fee(mainly for content on the PSN Store). Also, for the first couple of months for any DLC content that is hosted by Sony has a bandwidth cost for developers. Every GB consumed by gamers(demos, movies, add-ons, etc) cost $0.16 for developers. So if 3 million PSN users downloaded the RE5 demo prior to the games release, that's a little bit less then $400,000 Capcom is shelling out too Sony.
For gamers there are only two real negatives to Sony's way of doing things. Developers do to take a second guess with DLC content and online multiplayer. Plus, if a game looses popularity or server maintenance becomes expensive the games online component could be shut off for good(PS2 games for example). So even if PSN gets bigger like Xbox Live, unlike Microsoft's service games are still threaten with loosing connectivity in the future.
On the PC, it's the same way as the PS3. BUT! Getting extra content and video is simply universal. You're not just going to one company for all your online needs. You might have to connect to Steam to play Team Fortress 2 online, but only because of copyright laws. That too cost money for Valve. Connecting to a developer's network to prevent piracy is more common these days then ever before on the PC. You could connect to a lone-sharks server to plan an illegal copy of a game, but the person who's hosting that is also paying extra cash so you do not have to agree with a TOS.
The reason why I brought this up was simply because of Ace Combat 6's online multiplayer on the Xbox 360. During the weekday there is little to no activity when it comes to online dogfights. And you might not even be lucky to find an online session or two during the weekend. I was wondering, if that game was available on the PS3 would it's servers for online multiplayer be shutdown?