I think you're laboring under a misapprehension. This site (Ask Ubuntu) is not affiliated with Canonical and is instead a project of a completely different company: Stack OverflowStack Overflow.
While there is some sort of agreement between the two companies and Ask Ubuntu is listed as an official help site in Canonical products, the two are separate entities and Stack Overflow isn't particularly passionate about open source or libre software. They're not against it, and they even have some open source projects, it's just not something that's very important to them. As far as I know, the people who originally set it up all come from the Windows world.
So yes, Ask Ubuntu isn't on the Canonical servers, it isn't affiliated with Canonical (apart from serving as a useful place to get help for Ubuntu) and you shouldn't expect it to conform to the same principles as Canonical. In fact, this site is part of a whole network of Q&A sites (the Stack Exchange network) and Ask Ubuntu is just one site among many.
All that said, Stack Overflow, the company, is actually pretty good about security and they do take their user's privacy very seriously. They just have their own rules which are not necessarily the same as Canonical's.
So, if you feel that this site doesn't behave in the way you would expect from an official or semi-official Ubuntu help site, that's something you should take up with Canonical, not us.
The rest of your questions about what each of those URLs is used for, I can't answer. You might want to search through http://meta.stackexchange.com, the main meta site for the Stack Exchange network or ask there.