As the title states, what type of software is running these sites? They look like myspace-type social networking clones: http://www.itsmynissan.com/ http://www.automotivepartsreview.com/arkan997
Not sure what exactly those are, but you're probably right. http://www.google.com/search?client=opera&rls=en&q=myspace+clone&sourceid=opera&ie=utf-8&oe=utf-8
Both of those sites are .net, so they could well be using h*tp://communityserver.org. For a free PHP/MySql version, try PHPIzabi h*tp://www.phpizabi.net