Content SPAM – How Do I Prevent Spammers?

I just logged into my dashboard for a social platform I built using CakePHP.
Unceremoniously, I noticed that today I had so many feedbacks and comments.
Now having feedbacks and comments on your site seems like a good thing and sort of gives an impression that you are gaining traffic.

However, when these comments and feedbacks are totally useless and have no relation with the content you have published, then that’s certainly not a good thing.

Normally, I would have placed a CAPTCHA verification box for every public form, but I am of the opinion that using a CAPTCHA is somewhat repulsive to some people.

After pondering for a moment on how to implement a realistic and non-obtrusive verification, I decided it would be best to allow comments and content from registered users only, as well as keep the feedback form open, with a script to filter out spam content.