An "edu backlink" is simply a link from a public institution (University, High-School, etc) that points back to your page. These websites have a huge authority in real life but also in the search engines. Since authority is transferred in the same manner as Pagerank the more quality .edu's, the better.
High DA – We filter sites for Domain Authority in addition to high Page Rank to ensure clean and powerful línk juice to your site.
Both do-follow & no-follow backlínks – We use both
link is=== http://blog.bdblackcat.net/