re: BBC article
So long as they're not charging money, I don't particularly see the harm. But then, I also support fanfic for similar reasons.
Private servers give you a chance to play around and try things without messing things up in the shared game. Running a private server gives people a taste of how much work the real thing actually is. Many people play on both the paid game and private copies of it. Private copies are NOT an adequate substitute for the shared universe of the 'real' deal, they're not a disincentive from playing.
And especially in the case of MMORPGs where you were forced to pay a box-copy price as well as an ongoing server price (sadly too common), private servers provide the ability to play the damn game - which you paid for - even if the company explodes. An awful lot of MMORPGs get shut down. Bought a box? You have a coaster. Sucks to be you. (And people wonder why I tend to be resistant to MMORPGs?)
Now, obviously at the point where a private shard starts charging people to play, then the moral issues change. (Although being pretty open-minded when it comes to IP, I'd be fine personally with them being required to pay a percentage of take back to the dev studio... but that's me, not everybody.)