Educational, Government, Military Domain links will Increase Page Rank

There are criteria to quality links and I think all these criteria followed by .EDU, .Gov, .MIL domain also these domain are more trustable and authoritative domains for general people and search engine so there is general concept that to get link from these domain will be more attention than other domain by search engines.

Criteria for Link Quality Building

Links should be PERMANENT
RELEVANT Sites - all links from relevant related on-topic sites
High PR link will be better
Links contain TARGET KEY PHRASE as a text hyperlink
WHITE HAT - No redirects, JavaScript links, hidden links, Flash sites/pages, or other unethical or black-hat tactics
No FFA, guest books, links within forums, links within newsgroups, links farms or any other free editable site like orkut.
No more than 30 outbound links on each web page (where link is placed)
One link per domain, all from different c-classes/different IP's
Fully indexable by google-bot and index on the 3 major search engines (Google, MSN, Yahoo)

What is Page Rank
PageRank (or "PR") is a way to measure the "value" of a page per criteria set out by Google. There are maybe a hundred variables that go into determining a site's PR, but the two primary factors that can be controlled are content and in-bound links. Content tells users (and the engines) what your site is about, and inbound links to your site are counted as "votes" or "referrals" by others. Other factors include the age of a site, what type of domain it is, such as a dot.edu, dot.gov, dot.org, or dot.mil, and whether or not the site is optimized. PR is used in general to determine where a site ranks for certain phrases - utilizing content and page titles to determine which keyphrases. If a PR 7 site and a PR 5 site both have good, quality content around the same keyphrase, chances are that the PR 7 site will rank higher.