Reason #12523 I won't pay full price, or a monthly subscription for a MMO:

APB, which was released in June, having sold god knows how many yearly, multi-year, and "life time" access subscriptions, has been shutdown, along with its development house.
The game was trashed in just about every review on launch (much like EVE was when it was new), but I guess APB didn't have the financial ground to fix how broken it was.