MyBB Community Forums

I have a small forum (less than 10 members) and it doesn't have a lot of activity. But rather often, it reports that there are many guests active (sometimes over 100), even though though there are usually zero or just 1 or so. It is very "step-like" (few or many and there is no in-between). I noticed before that "Google" was showing up as a user a lot, whatever that means. Are these possibly bots? I can see Google scanning the forum every once in a while, but it happens rather frequently (a few times a day).

It is a known issue with MyBB 1.8.22 that the index page member count is counted wrong - no solution for it that i know of so far, but I assume it's not long until we see one.
However, it is also possible that there are a lot of bots on your website too. There are a lot of them around, specifically targeting MyBB and other forum software, usually for spam.

See https://community.mybb.com/thread-225918.html (adding custom bot strings to let MyBB detect them correctly)

i have the same problem..sometimes its about 400 guest every 1 hour and all of them are rating threads