After 3 days research,I found bounce rate is more important than ever,Google use it as rule to evaluate your site's quality. so if your site is not content farm and you was hit by Google Panda,you can try to optimize your bounce rate.
Absolutely correct Edward.H. Most of us never look at bounce rate and only bother about the number of unique visitors and page hits. What I feel is that having very good page hits and unique visitors with high bounce rate is of no use. I have written an article on how to reduce bounce rate in my blog before. Below is the link if it helps somebody. 7 Sure Shot Ways to Reduce Bounce Rate Thanks.
I Agree Edward. Place Related post, Site navigation (eg for the current page: Home > Forum > Marketing > Search Engine Optimization), tag cloud and proper category linking