I am using 1.74 and I get a lot of spam registrations. Recaptcha and IP limits are there but all the spammers use different IPs and solve recaptcha and logical captcha. Then I added another registration field and then I noticed that all these spam registrations use same info on the added registration field. So it appears that a single spammer is registering profiles. I suspect this is done with an SEO link building software such as GSA search engine ranker which can employ human-based captcha solving services such as deathbycaptcha. Is there way to restrict the user registration if a specific answer is given to an extra field (as in my case)?