Not all websites are dot com, even though it’s the most common. For seo purposes you don’t need to know technical detail, you need to know more what works best to improve rankings.
A website which is not a dot com, but a dot org or a dot edu still is a website. If no other website links to that, it’s still a low quality website. I can go register a dot org and put adult content on the page. The site gets listed as bad neighborhood if I use black hat strategies on it and get caught.
So the point is, getting a link from a dot org or dot edu is not a better or more quality in some way or another. Authority sites are sites that a link from is great, but not all dot org websites are authority sites even though they may look like. Not all dot edu sites are authority sites just the same.
In general Google treats all domains the same no such preferences are given to domains with dot org and dot info and dot net are also not give less preference. All domains are treated equal.
From an seo point of view you should not worry about finding these org or edu links because they are the magic pill, because it’s not the case. So don’t ask the government website for a link exchange… Seriously speaking it will be a waste of time since Google does not treat them better in some way or another.
Since Google said links from authority websites are better, most assumed that org or edu websites which are most common with government sites and the like have something special. Authority is not the org or edu, but the site itself, the quality of the site, how many others link to it and other specific details related to quality and linking of the site.
Trying to find them is the painful road. Google primary objective is the searcher. Giving him the best results. Like I said you can go register a dot org right now and then register a dot com at the same time. If both domains are brand new, you still have not yet added content to them, then why the dot org should be known as better than the dot com.
Makes no sense, for the searcher he does not care whether it’s com or org. You can easily buy org domains in bulk and put content in them, then cross link them, and there you go you have high quality links from dot org links. That’s a loophole and Google has a way around all loopholes. So something silly as org or edu domains will give you a better quality link does not exist.
Take advice from the King 
Tags: Link Building
I believe that the use of “dotcom” is steel the domineering web compared to those website using “dotnet” and the like. dot com is widely been used by everybody.
You’re right, most people online buy dot com’s it has a more professional image… it’s like the “default” on the web… if you are selling from your website dot com is always the best choice.
Thanks