They do have a customer agreement and that agreement specifies that it would only be sold to a company that would be continuing the service clear provided for the customers that still had time left on their membership. They were still pushing the $199 renew fee pretty hard even as they went out of business though.
They do NOT issue sequential last four digits any more. They used to, e.g. my mother is a fraternal twin and she and her brother have consecutive SSN's, I too am a franternal twin however, the only thing that my twin sister and I share in our SSN's is the first five digits. The last four are unrelated.
I graduated from Central Michigan University in May 2008. While the current network policies may seem restrictive, I did live in the dorms during the 2003-2004 school year, and between xbox gaming and unlimited p2p filesharing, we had to survive with bandwidth that had the throughput of a coathanger. Average download speeds would rarely top the equivelent of dialup. I know that there is a plethora of affordable off-campus housing in Mount Pleasant, most of it with broadband included in the price of rent. If you aren't trapped by the horrible if-you-get-any-scholarship policy that makes you live on campus for two years, I strongly advise you to look into it.
This is very similar to off-road use diesel fuel, which is also dyed. It is not uncommon to see a truck pulled over and an officer checking the tank for dye.
To begin with, I have not RTFA (damn you websense!) nor have I ever played WoW. But I can give some examples of addictive games that I have played, such as Sid Meier's Pirates! As many other posters have pointed out, one of the features that they feel makes WoW addictive is the social interaction. This has no appeal for me, which is why MMORPG's haven't ever really captivated me the way most single player games have. I think that the addictiveness has to take into account both the nature of the players and also the player's goals. In the case of Pirates! the game became very addicting because the quests that would be given to you could be accomplished in about 20 minutes each. This, coupled with a fairly intuitive control scheme using just the number pad on the keyboard made for a great pick up and play kind of game, but always having the ability to complete a particular quest in 20 minutes or less triggers a "just one more" kind of play style where I lose track of time and next thing I know I've been playing for 14 hours with minimal breaks. Having short, attainable goals that tie into a long term goal provides a sense of accomplishment that produces a desire to keep on playing without interruption.
To say that it was kept somewhat secret is true, but don't discount that many, many people knew about the extermination. The prevailing theory in most circles was that most germans didn't know what was going on, but after What We Knew was published it became apparant that wasn't the case.