I have heard about over optimization. And I joined an SEO Contest which ends pretty soon. I used to be at number 5, and now is at 13 to 15. And since it is the last month, I decided to buy high PR links which I think done me harm as I went down. Now, my question is... does anyone know a free tool online that can check the ratio of low PR inbound links to high PR inbound links? So I can check if my high PR IBLs might be going overboard and was achieved too fast, compared to the number of low PR links I have.