Hello Mark,
Well, I've gotten to the bottom of the issue now. What you experienced was not a virus or a hack, but merely a bug, which has been squashed now, and should not be seen again. The posts you saw, were old spam posts which had been partially deleted, but obviously not all the way. This issue has now been resolved.
In answer to your earlier question. If you were to have a virus it should not effect Creative COW. If this were not the case, black-hat hackers would quite easily be able to penetrate our systems. Gladly, they are not, and the COW is safe.
As I mentioned before, you should keep your systems and browsers up to date to avoid being infected in the future. Updates, a firewall, and virus scanning are the best methods to keep yourself safe.
Thanks again for pointing out this issue!
Abraham