I've implemented the solspce-ratings plugin on a client website and have enabled the captcha, but am still getting spammed. Any ideas on what else I can do to avoid getting spam ratings ?
The best way to beat form spam for EE imho is to use http://devot-ee.com/add-ons/accessible-captcha, which turns captcha into a much better working q&a. This has solved all automated spam for me.
I am using the add-on Snaptcha, 14 US$. The user has to type nothing, it uses the honeypot-principle and generates a invisible field; spambots trying to fill out this field are blocked. It blocks literally 100-thousands of spam-attempts on my site, every some weeks one gets through. I could highly recommend this one.