I don't know how to put this, but this kind of thing also bothers me when people agreeing with a person post comments and those disagreeing decide not to do so so as not to confront the person, and the poster gets a skewed view of his readership's attitude.

An example might be posting a picture and getting ten "you look gorgeous!" responses because the seven people thinking "ho-hum, just about average" and the five thinking "good heavens, that girls is ugly... and has no fashion sense, either" decide to hold their peace.

Or someone posting a controversial topic and getting ten replies of "oh, you're so right!" but where eight others who disagree decide not to post because they think the argument will be pointless if the poster is that convinced of his stand on the topic.

In both cases, the "don't comment if you don't agree with me" -- which may be voluntarily adhered to by commenters even if not explicitly requested -- bothers me a little.