Unfortunately, the default behavior of tracking bounces by Google Analytics is fundamentally flawed. Google Analytics defines a bounce as any visit where a user only views a single page. The problem with this approach is that it doesn't accurately reflect user interest. As an example, if a user lands on a page of your site, spends 10 minutes reading the entire article and then navigates away, Google Analytics counts this as a bounce. We view this interaction as a success since the obviously found what they were looking for.
We track bounces as single page visits where the user leaves in less than 30 seconds. We think that if someone spends more than 30 seconds on your site, they found something that is at least mildly interesting and shouldn't be counted as a bounce. Our approach is quickly becoming the standard way to measure bounces and we hope that Google Analytics will follow along.
If you're interested in learning more about this, here are some relevant articles: