Question
 

I was viewing the "Who's Online" menu, and noticed that Guests were sometimes called "guests", or sometimes "google spiders".

What does that mean?

Guests are actual guests.

Google Spiders are Google's bots indexing our content for the Google search engine.

oh....i never thought about how those serach engines worked. :P
so do we get yahoo bots and ask jeeves bots and stuff sometimes?

Yup. :)