Visitor Behavior as a Ranking Factor

[aristotle]

Is there any evidence that the Google algo uses visitor behavior as a factor in determining a page's ranking? Examples of visitor behavior could include:

1. How much time a visitor spends on a page.
2. Whether the visitor bookmarks the page as a favorite.
3. Whether the visitor goes to other pages on the same site.
4. Whether the visitor returns to the Google SERPs and chooses a different result.

When Google introduced its Chrome browser, some people speculated that they were motivated by a desire to get more information about this type of visitor behavior, toward the ultimate purpose of using it as a ranking factor.

What is your knowledge or opinion about this? Also, have any Google employees ever talked about it?

[tedster]

Here are some recent comments about bounce rates from Google folks:

I can tell you for sure that anyone visiting your site a few dozen times and hitting the back button on their browser is not going to impact your site's crawling, indexing, or ranking at Google. That wouldn't make much sense and would be too easy to abuse.

-John Mueller Google Webmaster Help thread [google.com]

I'll just say that bounce rates would be not only spammable but noisy. A search industry person recently sent me some questions about how bounce rate is done at Google and I was like "Dude, I have no idea about any things like bounce rate. Why don't you talk to this nice Google Analytics evangelist who knows about things like bounce rate?" I just don't even run into people talking about this in my day-to-day life.

-Matt Cutts Comment on Sphinn [sphinn.com]