What’s a preferred site structure?

Matt's answer:
CUTTS: Here’s a question from London. Katy Bairstow asks, “There seems to be little impact on human visitors where in the site’s structure a given page is, so is it better to keep key content pages close to the root, or have them deep within a topical funnel-structure?” Well, this is not SEO advice. This is just behavioral advice. If you can have stuff, you know, fewer number of clicks from the root page, visitors are more likely to find it. If somebody has to click eight times to find the page to register for your conference compared to register right on the main root page, fewer people are going to find it if it’s all that many clicks away. So it doesn’t really matter where it is in the path, like is it at the root level or is it eight levels deep. It might matter for other search engines. But at least for Google, I would think more about, you know, can your visitors find it. And that’s not search engine ranking advice. That’s just general advice on how to improve your ROI.
by Matt Cutts - Google's Head of Search Quality Team