Fatum

Hope it will be explained in the below posts.

Whats the best way to boost link popularity with our own sites.

a) Linking all sites from some text keywords,put it to a table and paste it to the bottom of all sites, all pages.

b) use transparan , or 1*1 pixel gif name them something related with site and link from them. Also fill the alt tag and replace the images wherever you want.

c) your secret way