When I read the answers to the question, some of which I answered, I don't see SPAM.
I am signed up for e-mail alerts, and there have been TONS of spam messages the last couple of days. They must be deleting them after the fact.
the spam message is the same, someone simply keeps joining under different names & becoming a nuisance! they've fixed the flag feature, so all that needs to be done is click on it when the spam crops up!
I've seen the spam message posted among the email alerts I have as well.