Yes, all of those visitors are actually search engine spiders. Well, not all of them but I think it's safe to say most of them. They're merely here to index all of the content on the forum. Then, when someone searches for, let's say "SMT driver opinions," a post from Golf Rewind may show up as a search result.

In the future, I'll try to find some way to keep spiders off of the online now list. After that, I can reset the "most users online" count.