I'm from Germany. We have quite strict rules when it comes to data protection and our lawyer strongly recommended to not use re-captcha or any other non-european service for spam prevention. Bots bypass the image captcha and our customer does not want the questions. So CB Antispam is useless for me.
Is there a way to replace the community builder registration form with a different form? We use RSForm as form generator which includes a hashcash field for spam prevention, which seems to work quite well and I'd use this