Link exchange is not something Google recommends is you are doing SEO! However search engine optimization is not always done by the book and many use shortcuts (black hat SEO) to make fast improvements to PR (PageRank) and rankings. However it's been demonstrated over and over again that such practices sooner or later lead to website getting banned from search engine or complete lost of PR and ranking s.
You should only exchange links with websites that will include your link in their home-page and not put it into a page with whole bunch of other links.
The site you are exchanging the link with should not be involved in massive links exchange.
gratis, chatear y buscar amigos en chat gratis o ligar. Citas, contactos y encuentros.