Static URLs are indexed much more quickly than dynamic URLs, if dynamic URLs get indexed at all (and no, not every engine indexes dynamic URLs).  Like you said previously, only a minute fraction of your old dynamic posts made it into Google.   

From what I’ve seen their indexed the same. I have to wade through dynamic URLs from message boards all the time.

 So most are going from something like this: http://www.congenitaladrenalhyperplasia.org./forums/main/thread.php?threadid=12345&sort=date

to this:

http://www.congenitaladrenalhyperplasia.org./forums/main/thread.php

A search engine wants to only list pages in its index that are unique. Search engines combat this issue by cutting off the URLs after a specific number of variable strings (e.g.: ? & =) and dynamic and script posts often exceed this.  So my understanding is that you probably have a bunch of URLs like the one above and that is holding you back in the PageRank. 

Each post has only two variables, the board and the post #. I hardly think they would have cut it off any shorter than that.

So if you are rewriting the URLs and making each page unique html (maybe this is where we are talking about two different things?) and therefore more agreeable to a search engine, they’ll be indexed easier and faster.  Google will spider directly (if html) and perhaps frequently, and that will produce more posts as pages as search results.  This is how other forums with a bunch of activity display pages of post results after a Google keyword search.  I don’t see how you get around this in the longrun if you are doing the rewriting. 

But Google’s not indexing them, I am. I have the sitemap registered with Google and they refer to that rather than spidering it themselves. That saves them resources. I’m actually spidering it as I write this. The spider’s been running all day, and either tomorrow or Monday I’ll upload the sitemap then notify Google that a new one has is ready.

Are you using some sort of "cloaking" type rewrite software that allows you to get around this and revert back to the dynamic and fool the search engines?  Otherwise, I don’t see how you boost your PageRank and get around not displaying more posts as search results.

I do format the pages differently for the spider so what’s displayed in the search engine is easier to understand, but the fact remains that there is so much competition for placement in search engines that older pages really don’t have much changes of being thrust upon people very often. I was commenting to my wife today that that’s one advantage of internet porn. The pornographers are all scrambling sp frantically to get the attention of the sickos that it make it that much harder for them to find sites like ours.