.net wasn't for community for sites, it was to supposed to be used by companies dealing with network infrastructure such as web hosts, ISPs, DNS hosts, etc.
ya dman is right. But .net now is almost become basically a site on the internet. Kinda like .com in the perception of lots of people. .Org however still maintains the idea of content and information. If I saw a .org site that had no content but just selling stuff, like an E-Commerce site I would think it was arkward. But If I see a .org that was content rich or something you can read for information it makes perfect sense, sometimes even more than .coms. For me at least
I have no comment for .net It seem no different for me, I even have no problem with .biz for such a search term on SE