Internal Link Graph: "focused PR" or "spread it around"?

[Tonearm]

It seems fairly clear that rel="nofollow" can be an effective way to prevent PR from flowing to your unimportant internal pages, but what about the way PR flows through your important pages?

Lately I've been thinking about what the optimal structure of the internal link graph presented to Google must be. Should it be tightly focused and strictly structural with liberal internal use of rel="nofollow", or should there be as many internal links as possible on the link graph without regard to the structure of the site?

An example of a very strict strictural link graph would be like this:

Home links to Categories
Categories link to Sub-Categories
Sub-Categories link to Products

Every other internal link would be be rel="nofollow". This is intellectually satisfying and clearly demostrates the site's structure to Google. On the other hand, would this detract from what tedster describes as "internally generated PR" and reduce the amount of PR flowing throughout your important pages?

Does anyone know which type of link graph Google favors?

[tedster]

I have never tried to sculpt PR this intensively, but I have seen sites that do, and usually because they are crying to me about lost rankings.

From what I've seen, I'd say it depends on the individual site and how it would circulate PR before the no-follow sculpting. As a general rule, I tend to "treat googlebot like a regular visitor" and only do PR scuplting in those cases where the waste of PR is pretty clear.

This sounds like an interesting test to make, if anyone has the inclination to do it.

[edited by: tedster at 5:51 pm (utc) on Feb. 26, 2009]

[Shaddows]

My 0.02 is that you are losing more than you might be gaining. Look at Wiki. Little structure, lots of ranking. Thats due to all those inline, contextual, relevant internal linking. There is an outstanding thread somewhere that made it to the front page discussing this in finer detail.

I'm all for structure, but focussing on PR at the expense of semantics is heading in the wrong direction.