I think you better read Cypher's post. Just because you'can't afford to play' and because it 'teaches you how to script', doesn't give you the right to copy right their material.
I don't think Blizzard has the intention of shutting ALL the servers, because let's face it, that will be impossible. I think they want to shut down the private servers which are making a profit through donation and selling custom weapons/vendor.
But from a legal stand point, this is just the start. Sending a Letter of Notice, isn't really that hard and time consuming, so when people say they don't have the time ect, I think your very mislead. I think where the Blizzard vs Private Server battle will take a decisive step is when one private server, which ever that may be, decided to take it to court. In my opinion, they really have no legal basis for an argument for running a private server (from what I understand of US copyright law). Lets say for example, one private server decides not to close their server and Blizzard takes them to court. If Blizzard were to win that case, it would set a precedent for any other lawsuit involving/relating to WoW and private server. Once that is set, any other private server that decides not to to close down and take the matter to court, will be bound to this precedent, and any good lawyer knows it's hard to break precedent making going to court pointless. Thus, sending a Letter of Notice could be just the tip of the iceberg. Closing the bigger servers sends a message to the others.