Still looking for the edge, many people at the beginning of 2006 swore by the quality and 'special treatment' of .gov and .edu web sites. It was believed that acquiring a one-way link from one of these sites would provide disproportion SERP boosts in comparison to similar .com web sites.
So what's the verdict? Do US government and education web sites enjoy special treatment in the eyes of the search engines? Well luckily Google engineer Matt Cutts debunked the whole specialized process by firing in one of his webmaster videos:
"… in fact we [Google] do not really have much in the way to say" Oh this is a link from the ODP, or .gov, or .edu, so give that some kind of special boost. " just those sites tend to have higher PageRank because more people link to them and reputable people link to them. "
You can not get any more concrete then this, however, many still have 'gut feelings' that .edu and .gov have more than meets the eye. Essentially Matt Cutts is saying, and we should all believe, the link address has nothing to do with its strength, however, the content does.
.edu and .gov have high PR because the content is of a different nature than .com sites, typically trusted and unique. Many people link to these sources and hence the great PR. Webmasters still debate that there is a hidden trust factor for .gov and .edu sites.
A trust factor MAY exist, however, again, it has been EARNED because of the content provided, the volume of the content, the nature of it, and the number of incoming links. A .com site CAN have an equal trust factor if its content and incoming links were the same.
All things being equal, .com and .gov and .edu have zero difference in terms of link value. It's the nature of the content that is paramount and the deciding factor in any PR weight.