SEO doesn’t mean link farms

One of the latest website building strategies discussed by many internet marketers these days is the building of networks. Networks are several small sites, also known as baby sites, that all feed into a much larger mother site.
Typically, you would build 5-6 baby sites for each mother site. The strategy is said to be very lucrative from an affiliate commission point of view because it is based on on-page search engine optimization and calls to action to the viewer. Each page on the site is linked to each other and then they all link to the mother site.
One has to follow the on-page optimization strategy very carefully to ensure that you don't fall foul of Google's dislike of link farms. As always, links must be relevant, otherwise they don't make sense.
Just another strategy to make money online. Do you have any to share?