If it's of any help: All accounts with an ID >= 8184, except on Writing for the IDs 8200, 8227 and 8240 and on Meta 8196, 8198, 8219 seem to be SPAM accounts (please double-check to prevent innocent accounts from being deleted, though)

This is, unfortunately, an ever-growing problem. On a synagogue site I maintain where I used to get a handful of spam signups a month, I have started to get a dozen or more every day. In that case, I renamed the original signin script and added a message on the registration page to email webmaster to sign up. That isn't really an option here.

Best practices is a double opt-in like we have for the codidact.org announcements list - request just sits in an unseen pending queue until user verifies by Replying to (or clicking a link inside) the confirmation email. No idea what would be involved to do that for QPixel. I have written such things before (the codidact list is a 3rd-party product, so I didn't actually have to write that one) - not terribly hard to do.

@manassehkatz While that certainly raises the bar quite high for the spammers, it is still beatable by spammers creating throwaway email accounts on the fly. The entire process including "clicking" the link can be automated. If we ever get such a "determined" (?) spammer, we could include a random "puzzle" on the sign in form. Not Google's CAPTCHA (eww!), but something like "3 + 2 =?" Still not unbeatable though.