CainIV - 5:33 pm on Aug 6, 2009 (gmt 0)

It my estimation, unless each page is brilliant, one page websites rarely 'deserve' to rank well for any keyword terms that are competitive.

"Some are selling things via amazon affiliates, some are not. Yes they are for the most part lean of content. "

As others have mentioned, that statement alone sums it all up. Google wants unique content, not stub landing pages - especially ones thin on content with affiliate link ads.