Weird spam messages that don’t have any links are often “probes.”
The idea is fairly straightforward:
1. A spammer spams a forum, blog, guestbook, Web form, or whatever with a seemingly innocuous post. Sometimes, the post is generated by software that produces gibberish that sounds like it might be plausible. Each one of these posts is unique; the spammer never uses the same exact one twice.
2. After a day or two, the spammer uses automated search tools to search for the spam posts. The automated software keeps a database of the unique spam posts and the forum, blog, guestbook, or whatever where it was posted.
3. If the Web search sees the spam post, then the spammer knows that particular blog or forum or whatever isn’t running effective antispam or IP blacklisting defenses. Now all of a sudden the address of that blog is more valuable to the spammers; the address of the forum or blog will likely be sold to other spammers and “black hat SEO” operators, and slammed with spam like whoa.
If you know the commenter….fine. If not, check it’s a real comment. If not….spam !! Never approve !!