Guests is normal. Not everyone uses an account and contributes: leeching is common on forums. Robots, of the somewhat 20, most are bing/google: people do use the normal browser search engines to find content. The others have minutes between each search so that would be very poor data mining. Some B4X users have written tools to find stuff so it looks they could be them. And I'm sure there are mechanisms in place that would detect weird things (e.g. like as DoS filter).