I should also point out that it isn't always prominent posters who ignore people who post less in favor of agreeing with other prominent posters that they're friends with.
I have been ignored by posters that have very few posts on many occassions where they will agree with something somebody like Roy or Faf say even if it's exactly what I said. (Just an example not sure if it's true with those particular posters)
It's not because of friendships or people being rude... although that is still an issue... just a separate topic. It's because people's eyes are drawn to the stars and large pos counts and TP counts. People who have been around longer also tend to have banners and avatars and what not. Newer posters may become victims of being ignored because they're posts simply don't seduce reader's eyes.
I think there is some truth there. Also, speaking as one of these god like moderators who are completely separate and out of touch with you silly small minded peons, when I see a poster I know has a history of responding back to posts I make, or engaging in active but hospitable conversation, I'm more likely to respond to them than I am someone I don't know, or have a history of getting into 'incidences' with.
Personally I don't come here to see my witty one-liners and 90's pop culture references just sit around like a rusted 91 Ford Escort on a redneck's lawn. I like the conversation, and yeah, I'm more willing to respond to people I know will write back.
Its not a rule of thumb or even a general rule for me, its not like I don't respond to people who are new, but if I see someone who I know will respond back, whether they're prone to agree or disagree with me, I am more likely to say something.
I'm sure most mods will disagree because they never agree with me when I point out the gap between mods and ordinary posters... but it does exist.
I think in this discussion its silly to make it about Mods, because we're talking about high volume posters. While all mods are high volume posters, not all high volume posters are mods. But, since you bring it up, I don't know what gap you're talking about between mods and posters.