>What is the idea behind a message board then reproducing the content? Do I understand I can read for fun and not pick the ideas and use them?

The paragraph which presents those bullet points refers to "a part". That means a massive content, manipulation of a certain amount of content and so on. It does not relate nor restrict about ideas or making references to anything in it.

>Impossible. Any browser will store the content in it's temp / cached storage.

I do not know of any browser capable of extracting a Web site database located elsewhere on the Internet and brings it locally.

>What is the whole site worth if I can not use it for business purposes? I code to earn a life?

The non-commercial reference refers to forbid someone to grab content and use it for commercial purposes, such as selling it, using it for promotional material and so on. It does not forbid, again, the acquired knowledge for your own personal benefits.