Can you tell me why I’m suddenly run into this problem?
You site has become known to spammers who circulate lists of sites that allow wordpress registration. Bbpress simply uses wordpress registration, so that is the route they are getting in.
I delete 2-10 topics/replies a day on this site that are spam.
I’m not certain, but I think that something like Wordfence might help with this. I’m running it on three different sites. None of them use bbPress registration, but two of them have MemberPress registrations, which are vulnerable to the same problem. Wordfence doesn’t exactly address this problem directly, but they do apparently keep a huge list of compromised and other suspicious sites, which get blocked.
Again, I don’t have any direct experience with bbPress registrations, but this has really helped me with various kinds of spam logins, comments, and other problems.
Just a possibility.
Akismet is the biggest help with this. And yeah I think Wordfence helps too. I’m getting hundreds of spam registrations a day. There are a few registrations getting through the spam filter that are suspicious, but not definitively robots. Hard to tell…
I wish for a spam solution that has more configurable settings than Akismet though. Some genuine topic replies getting marked as spam.
Some kind of captcha on the registration page? As for my site, I’m avoiding doing that because the non-tech literate users, but there must be some kind of plugin out there that adds that?
Yes I have Aksimet installed on my website, though it does work out to catch spammy topics, but unfortunately not spam registration.
Recaptcha seems a good choice for now. Will definitely use that and see how it’ll go.
Never heard of wordfence, it might also be a good choice so, lets give it a try too.
If you’ve got a Captcha plug in, I don’t think wordfence will help any further with spam sign-ups (although it would certainly help with other types of hacking attempts, if you don’t already have any kind of firewall).
Wordfence Security – Firewall & Malware Scan
They also have some pretty cool security tutorials, if you poke around on the wordpress.com site.