SEO Plugin For Firefox.....Check Your Links

I made an interesting discovery today that made me extremely excited me one minute and had me down in the doldrums the next....I installed the SEO for Firefox Plugin and it shows which links have the rel=nofollow tag attached to them. It displays these links in bright red. I also just found out that a some of the links that I exchanged and payed good money for in the last couple months were worthless. I guess I got fooled because some of them still showed up in Yahoo when entered the in Yahoo.