My feed is full of former groups being overrun with blogspam. I've noticed it spiking in the last 3-6 months. That type of thing needs armies of people, and... well, facebook doesn't care.
Like the pre-google (well, and google search as of now) search engines, being overrun by spam signaled the end of the viability of the product. Either they don't have the resources to defend it, or they don't care. Reason doesn't matter.
