There is not strong evidence that Google had out ruled Reciprocal link building activity for the websites.
In my opinion Reciprocal link exchange is not much important in the present trend Optimization trend but due to the reason that more and more people exchange the links with a mutual understanding without any relevency between websites.
This technique is identified as spam. In general Reciprocal link exchange will benifit us provided the following three major factors are satisfied:
1. The other website who links us should have more page rank from the page where our link is placed which implies more visitors to that page.
2. Two websites should be related to eachother.
3. There should not be more than 25 outbound (external) links from that page.
Finally, one should not only rely and stick on to one or two techniques while building backlinks to a website, but they should adopt to Natural link exchange techniques too, such as - Blog comments, Article comments, Social bookmarking links, Submitting articles to digg, technorati among others.
