4 months ago, I started building links for my 2 websites. One is a national site and the other is local. I built links for both sites in the same fashion. Some of the links are from the same sites. The links are made up of paid directories and contexual links in articles. The national site has done very well. It really took off. However, my local site actually lost a lot of good traffic. How can I figure out what link may have caused the issue?