I have not really paid much attention to this method of link building until now, but have now decided to give it more attention after realizing how well this trick works. If you look around at the well-known Webmaster Forums you’ll find many people looking for a sponsor of templates they built. These Templates can be for forums, directories or blogs (in particular WordPress Blogs). These designer design and build templates for the software of their choice and then release it for free.
Under the license terms a user of such a template needs to leave the sponsor links intact. These links are usually located in the footer. By finding sponsors for their templates these designers actually make money. If you are a good designer it might take you an hour or two to develop a nice looking template. You can easily sell 2 sponsored links on a design for approx. $35 and $100 each. Depending on where you live this can be a significant source of income.
From a sponsor point of view this means if the template is promoted well, he get a lot of back links from other blogs. Imagine a free template with your link in it used 100 times – this can be significant if those blogs grow in popularity and Google Page Rank. The real beauty of this “seo trick” is not to concentrate on the publicly available sponsorships you find in forums, but to identify a designer who delivers good work and to contact this designer and to work with them directly. Bypass the middleman, bypass the competition.
In general this seems to be an underdeveloped market with high link building potential. If used in a mix of normal link building and SEO it can be a great tool to make your blog or website more popular. With Google and other search engines becoming more difficult to deal with you have to become more creative if you want to rank high in search engines.