Halfdeck - 5:55 pm on Jun 6, 2007 (gmt 0) Basically what I posted before.
Andy Beal just posted a short video of Matt Cutts talking about supplemental results at SMX:
If you got 60,000 pages, and you only got "this much" PageRank, and you divide it [...he mumbles], some of them are going to be in the supplemental index. Given "this many people" who link to you, we're willing to include "this many" pages in the main index.
Basically what I posted before.