PERMANENT: Here's a space settlement advocacy site worthy of some surfing time: Permanent.com.

Their focus is on commercial development of orbital resources and infrastructure, including sophisticated communications platforms, orbital industry (for both export to Earth and use on-orbit), propellant production, space habitats, and solar power satellites.

The main purpose of this WWW page is to reach out further into the engineering, investor, and general business communities, as well as the general public, to find people with a variety of skills who are interested in being partners in developing, openly critiqueing and refining business plans and mission scenarios which are realistically likely to succeed, as well as performing public and investor relations...

...Our focus is on certain "mission definition" topics which are outside of NASA's current implementations and which need work despite lack of much government funding. (We are leading, not following.) Topics covered on this website are such things as mining and processing asteroidal and lunar material into feedstocks for industry, the value and design of end products in space made from asteroidal and lunar materials, the economics of missions to specific asteroids, and other mission defining topics

There's a great wealth of content there, much of it in the form of an annotated bibliography of papers and proposals.