When you exchange links with a site and they are using the No Follow Tag then it will make the Search Engines believe all links pointing to that site are One Way Links since that site is using the No Follow Tag. You need to visit each site you exchange links with to make sure they are NOT using the No Follow Tag.

Enter your domain name in the top field. Enter the URL your link is placed on their site in then second field and type in the Verification Code and click on 'Check Now'.

Enter Domain Name Enter Domain Name where to search Verification