I have an account with Hostgator and somebody broke into my account. He than used email addresses to send tons of spam. Hostgator than blocked all my emails and I had to call them to see what is going on. HG told me that I have a key-sniffer toryan on my PC. But, when I checked my PC with ESET NOD64 it had found nothing. I bet, there was no troyan on my PC, just somebody broke into their security.
Now, something similar happened on a site of my client, although he is hosted on a different company. Somebody replaced all the pages in his blog to parking pages with ads. They somehow changed FTP password.
Is there some sort of gang going around cracking hosting providers?