That's a different kind of bot. Twitter bots are fake accounts that have been signed up and actually log in/use the service posing as real humans, but are in fact scripted programs. Thery are generally designed to influence people, mass distribute information, skew math in algorithms, and falsely inflate an idea, opinion, position, etc... When trending and influence data is based on volume, having an army of bots propping you up gives a distinct advantage...
On the other hand, "guest" traffic here is a hit from a non-logged-in user, be that an actual human "lurker" or web spiders and other automated indexing programs (which are also called bots). They are connections browsing/scraping the site as non-logged-in users.
They have different intended use cases but both types are still generically called bots. Maybe a good analogy is that a Ford and a Lamborghini are very different vehicles, but they're both still generically called cars.
This concludes my Nerd Talk. Please tip your servers.
(--Edit:
Going on a presumption that we don't have a lot of fake bots creating and logging in at BYC, but I may be wrong about that.)