Yes. But not in the way most people think. It's not about the total number of pages and the PR that is pushed up from the inner pages anymore...it used to be more that way. Now it is about the total number of pages on a particular theme. All other things being equal, if your site is about Basketball then having hundreds of thousands of pages on different basketball sub topics will put you higher in the SERPs. This is because Google can clearly see your site is about basketball and it has a lot of information about it. If you have hundreds of thousands of pages on different topics on your site then it will actually hurt you. Bottom line, it's about picking a theme or niche and building a lot of content around it to compete for the biggest keywords. Of course, I'm not stating the obvious that none of the above matters if you don't have links from other related sites back to yours.
I've found that having content hosted on Google Sites counts towards the total volume of your site. http://sites.google.com is what I'm talking about. That's not going to show up in conventional (public) site ranking... but my results bear it out! For example, wordpress (both .com and self hosted WP) has 'pages' Blogspot does not... If you want 'pages' for a blogspot blog, create a google sites and the blogspot blog will outrank a competing blog (that does not have said extra content) I use Google sites for TOS, White Papers and the like I found it a free way to add to the bulk of my site. That said, Google sites does not allow for much other than text, not even adsense, no javascript, no amazon.com links to books you have for sale, no affiliate code. The thrust of this thread was 'total volume' of a site improving ranking and I've found that this works
freelistfool, quite a comprehensive reply, nothing much to add except that the content must be original and regularly renewed/added. localgoogleguru, interesting observation on sites.google. Never thought of it that way.
It depends on your struture your site, if you didnt do it in a good way, then a HUGE site will definitely hurt your rankings. IMHO
Number of backlinks also counts for ranking in Google.. Build quality backlinks to your site... I dont think size hurts ranking in anyway
Size does matter and it is directly proportional to two things. 1. Age of the website. 2. Traffic If, you buy a site from SitePoint with 5000 posts, that is no way going to get any benefits. But, in the long run, you may or may not.
A positive factor for your site ranking is its increasing number of pages. If you are talking the weight of a page - it should ideally not be overstuffed with pictures.