Here are some examples. Recently OutRun Online Arcade was pulled from the XBLA store "due to the expiry of the contract with Ferrari."
This game was only available as a downloadable game, and now we will never get our hands on this game again. And this is a reason why i hate dlc games, if the game had been released as a retail with on a cd then the game would live on forever.
Another example was the multiplayer online feature in Metal Gear Solid 3 that KONAMI shut down. The people who loved this game will now never be able to play this mode again.
There are also countless great flash based games that you only can play online in your webbrowser, but if the server should go down after some years.. the game will be dead forever.
As a retrogame player I think this is a very important issue. Maybe not many people thinks of this as a problem right now when all the servers are up. But how will the ps3 and 360 work in 20 years? Will the servers still be up? can i still download my games that i only purchased online? Probably not.. just look at Nintendos Satellaview that had a similar way of purchasing games "online".. those "servers" are long gone. But thanks to emulation the games where dumped and can be saved forever. And the current consoles will probably have the same problem
I would like more examples of games that where killed this way. And what your thoughts are.