From what I have read, and somewhat tested, those blocks of text do alot for your SE "ranking". I'm not exactly sure of the order in which a SE spider indexes your site, however, it is something like:
1. Domain
2. Title
3. Description
4. Meta Keywords
5. Text on the page (including ALT tags)
If the text on the page relates to the keywords, description and title etc... it will rank your site higher in the search results for those keywords.
Also, if the spider goes 3 pages deep into the site, if each page it spiders is different, but, the main keywords are still present throughout the pages, it gives you another ranking point.
This is just stuff I've read... I've tested very little, but, what I've seen from those tests tend to suggest that it is true.
One of the more recent tests was with my TGP. I modified my meta tags, and moved "fetish movies" closer to the front of my keyword list, and within a couple weeks, my site is now ranked #1 on Google for "fetish movies". Not sure what caused it, but, it has been #1 for about 2 weeks now.
However, if the keyword frequency is too high, the spider will drop your ranking for "spamming", and you may get banned. Somewhere there is a list of the "allowed" keyword frequencies.
