Reciprocal Links are based upon an agreement between one website and another.  Both agree to place a link to the other on their respective websites.  When the two sites have visitors with related interests, this arrangement will generate quality traffic.  If you have volumes of quality reciprocal links, you will generate volumes of quality traffic. 

Another advantage of reciprocal links is based upon their effect on Search Engine Rank.  Search Engines are placing increasing importance on Link Popularity.  Generally the greater number of related links to your site, the greater your link popularity will be.