The Bill Gates re-emergence on Facebook--coupled with the newly launched Bill Gates Twitter feed--seems to have been done with a common purpose: to promote his foundation, as well as the new Gates Notes site.

What is The Gates Notes? Although described on the landing page as "an inside look at global matters," it's basically whatever Gates wants it to be--which at this point seems to be a combination of travelogue, book reviews, "Infrequently Asked Questions" and other articles centered around the issues that the former Microsoft CEO addresses through his foundation: global poverty, philanthropy and the like.

"Infrequently Asked Questions" seems to be one of the more interesting areas of the site. "You don't seem to be doing anything about global warming, which clearly threatens our existence," wrote one submitter to Gates. "How come you don't care about this issue?"

("If you have a promising idea about sequestering carbon, or a cheap nuclear plant or solar photovoltaic, you should get the capital to build plants, to hire people and to demonstrate whether [it] works at scale," Gates wrote in response to that one. "This is perfect for the marketplace. But it's not something any foundation should try to do.")

The casual reader might not glean much from the site about Gates' business acumen, or Microsoft (which goes virtually unmentioned), but it provides a good deal of insight into the man's thinking on the big-picture issues. And when you're throwing tens of billions of dollars at those issues, what you're thinking takes on a particular import.