tedster - 6:13 pm on Oct 12, 2006 (gmt 0)

[with &filter=0 added...] Smaller, newer sites continue to only show one or two pages, despite the fact that these newer sites have dozens of other pages that are relevant to this keyword.

Here's how I interperet that. The SERP is telling you that these "dozens of other pages" would not rank in the top 100, even if the 2-url limit is lifted. The first place I would look - not enough PR and backlink influence. Also consider every factor we talk about on the forum -- unique title tags and meta descriptions, no duplicate urls, etc.

If you've already got the goods when it comes to valuable and relevant content that the market would value, then make sure that "relevance signal" is as clear as you can make it.