What we propose is that all content on the site be subject to the Creative Commons license which would allow content posted to LessWrong to be used for commercial use as long as the work is given proper attribution.

Aye.

Most objections that come up could be dealt with by making this the default and allowing authors an opt-out clause. For instance, someone who wants to post excerpts from a paper or book that they plan to publish under different terms.

Along similar lines, another potential problem is posts that contain quotes from other works; quoting is "fair use" but I'm not sure this still applies to a reading of the quoted material.