Webutation 2.0.4 is trully upgraded Rated 4 out of 5 stars

The add-on works very well, nothing to do with past versions.
Sites' ratings has no impact on site's access/page rendering.
Webutation.net is accessed via SSL, unavailable otherwise.
One regret, hence 4 stars, no privacy policy available.
Webutation.net is not called on browser start (if start page not on the Web of course), and that's good.
Webutation.net sets a cookie when visited (not otherwise), absolutely not required if no login. Login allows participation to users' comments, and login is only via Facebook, which prevents users who have not a Facebook account from participating. Facebook is not the Web, be it reminded. Cookies were meant to keep user's data, not to set a flag. They all do it nowadays, those who don't are an exception.
I'm testing this add-on, perhaps for several days, my opinion is that of what it is as I write.

This review is for a previous version of the add-on (2.0.4.1-signed). 

Good references Rated 4 out of 5 stars

On Webutation's 'about' page is mentioned :
"queries
* Google Safebrowsing against badware an phising fraud (which is used in Firefox as well and updates every half hour).
* Website Antivirus which scans sites against adware, spyware and viruses.
* WOT which collects some reviews about websites.
I believe the idea is to aggregate different sources and sum up a global score. The idea is good, let it grow.

This review is for a previous version of the add-on (1.0.0).