This is not just a Google question, so let's take it from a broader perspective. G may be big, but they are not the only game in town and the question applies to all major SE's anyway.

The short answer is: Yes. That is assuming that you're not producing tons of duplicate content.

I'm not sure which SE mentioned this (I think it was Google), but in any case the comment was: About one half of our searches last year were on search phrases only seen *one time* that year. Witness the power of the long tail.

People search in an almost endless array of terms and phrases for what they want. The more content you have, the more possibilities you will have to pick up long tail searches. And of course as the world and markets evolve, and new topics or answers emerge, the continued refreshing and updating of expertise on your site ensures that your site will stay abreast of what's happening in the world, and therefore in searches being conducted.

Also, at least some of the engines are able to determine the nature of sites, e.g., that a given site is a forum. Question: If two forums exist in a given vertical, and one has 10,000 posts but none are newer than a month or two, and the other has 10,000 posts but sees many new posts being added every day, which do you think the engine might be increasingly inclined to feature over time?