Very interesting SEO article about Actual vs Standard Bounce Rates , and how search engines can tell the difference.
The basic principle here is that even if someone spends several minutes reading your page, if they don't click elsewhere in your site it is a standard Bounce. But if they click on to your page and back to the search engine a few seconds later, that is an actual bounce.
Most analytic packages won't make a distinction between the two situations, but you can still look at the average time on the page.
