I've look at current available content rating products (lovely.rating, RatingEngine, contentrating, ... also others). Most suitable was contentratings with its simple design and zope 3 structure, but lacks of plone implementation. So this is this implementation that was missing...
First release is targeting developers only so they can easily extend their content types and provide rating option for their content type.
Next step is making it available for all default plone content types.
p.s. i'm still waiting that plone.org project submitters approve my project and then i'll also post a link here.