Pero si compiten y mucho, tanto asi que veo muchos adsense orientados para que visiten sus paginas.
Es aqui donde mi duda cobra fuerza:
Cita: Google continúa recomendando no excederse más allá de los 100 enlaces salientes por página. Lo cual no deja de ser coherente desde el punto de vista del valor agregado que eso le da al usuario.
Y se incrementa con esto
Cita: A link farm is a form of spamming the index of a search engine (sometimes called spamdexing or spamexing). Other link exchange systems are designed to allow individual websites to selectively exchange links with other relevant websites and are not considered a form of spamdexing.
Search engines require ways to confirm page relevancy. A known method is to examine for one-way links coming directly from relevant websites. The process of building links should not be confused with being listed on link farms, as the latter requires reciprocal return links, which often renders the overall backlink advantage useless. This is due to oscillation, causing confusion over which is the vendor site and which is the promoting site.