This has been a common debate between masters for as long as I can remember and that is the importance and effectiveness of linking to a government (.gov) and educational site (.edu). Some people strongly agree with having these kinds of links as they are highly trusted by Google and have a great page authority which you can tell from the Page Rank. Other webmasters now disagree with having these sort of links due to the fact in which they can be highly irrelevant to the niche they are trying to target. This relates to the relevancy theory of back linking.
Google have claimed that these links are not better links but let’s face it how can they not be. They fit into Google’s guidelines of what a quality link is. They are well trusted, contain quality content and have major sites linking to them, the fact that it is also harder to get a link than most other domains is a big giveaway that they still are valuable. As with any link building there is always a group of black hatters who will buy thousands of .edu and .gov for such and such a price, which is why Google has come out and said something about it.
My advice is if you were to build these links then don’t do a high volume at a time as they carry a lot of authority and will not need as many as the average blog comment. It will also look natural as you will be building links at the average volume in a consistent manner and with a mixture of domains, which you can’t get better than.
How to build .gov and .edu links
To build these high page rank links, you will do them via blog comments and to find these you can do it a number of ways but like I mentioned above it is difficult to find a relevant edu or gov topic to your niche. You can Google: “keyword” + site:.edu “post a comment” this will bring up a bunch of .edu for the .gov just replace the site: attribute with .gov and voila you have a bunch of high PR blogs to comment on.
In summary I personally think that it can’t hurt to have a low number of these links just to mix up your link profile and keep it natural. Also they are some of the most trusted domains on the internet which Google cannot possibly ignore.