Weirdness with Tell-A-Friend

While running my EC site, there have been a number of times when I receive copies of some very strange Tell-A-Friend confirmations. I have no idea what these are. Are these hackers?

The "From" person would be some weird string like "ikllejsf" and a strange email address. They'll send the Tell-A-Friend to 4 or 5 different "people" all with the same weird names & email addresses. And the comment would be again something strange like:

"1ZpmG5  <a href=\"http://yxddvbbqjypo.com/\">yxddvbbqjypo[/url], xabtlmpeotbh, [link=http://vmmwtqnczaev.com/]vmmwtqnczaev[/link], http://skggucklbuvo.com/"

I've been placing their IP's in the Banned IPs template, but just curious if someone can confirm whether these are hackers and what they're trying to do via the Tell-A-Friend.

Thank you,
Ron

Spammers I guess - there's a similar issue with this site - about 99% of new users have weird email address/names - when I google them they come back with links to sites that belong to the twilight zone, hence they never get approved to post.