I'm not sure I pay a whole lot of attention to the post count, but rather rely on the content of the given post, or my past knowledge of the poster, before deciding on the reliability. I agree that many will be be more likely to give credence to those with higher post counts, or earlier join dates - this is human nature.
Perhaps if the "average posts per day" were visible, as well as the number of posts, it would allow those who actually give a damn to make judgments about those of us who hold their tongue (quality posters?) and those who chatter (quantity posters?) and the many who do a bit of both (look at
ajamieson - chatters quite a bit but when he says something about bmi - we all listen, because we have learned to trust his knowledge - quality & quantity posters).
I think it's a reasonable idea to exclude some of the "other" forums from post-counts, if you read post count as an indication of reliability. I think it's equally reasonbable to include them as an indication of participation.
Or we could just leave things alone - afterall, the world is not coming to an end, at least not quite yet. Sure, there will be occasional outbreaks of post padding - but we also have Moderators who do a fine job for the most part. We also have a Randy who will exclude people if things really get out of hand.
I think people just need to excercise their judgement on these matters. I suggest we leave post counts alone. I been here a few years and I've done ok - I haven't been damaged (I think

).