I'm happy that I found this service. First I have to mention that it is very easy to implement, also in non-Wordpress-sites. I have an old Contao site, where CleanTalk fails to integrate (it breaks the site). Then I tried CloutFilt and it worked immediately and now the form spam is gone nearly 100%. On another site, Wordpress, which is highly attacked from SpamBots, I have to say that CleanTalk is more effective, but CloudFilt does a very good job in protecting the site from most of the spam attacks. I guess this will be further improved. All in all I can highly recommend CloudFilt to everyone, especially when using forms.