How much does page length or number of words matter for Google?

[djingo]

I have a forum, presently with 25 posts shown per page. So if I made it 13 posts instead I would generate twice the amount of pages. This could potentially generate more variations over the same theme generating more hits. Question is when does page size become too small? Absolute number of keywords would go down, but keyword relevance in terms of "percentage" would be the same or maybe even go up ...

[tedster]

It's been a long time since I noticed any correlation between page length and ranking. I'm tempted to say that page length or word count doesn't have any direct affect at all on ranking.

It sounds like an interesting experiment to try. I would be concerned, however, about doubling the number of urls on your domain in one fell swoop. Such changes have been known to cause major ranking problems for an entire domain.