Just a couple of quick notes, since it's late:
You can get both traffic and pagerank if you post comments to blogs which don't use "no-follow" links. Just be sure you use your own keywords in your comment post - not blatant, but if you use a program like Neil Shearing's Real Link Finder (sorry, no hot-link here, but it's a free download) you can find blogs who have that keyword (phrase) in their text and so your comment would be right in line with theirs.
I've been taking a flying leap at the eBay community - which is more hard-nosed about making money than some of the other marketing I've been seeing. But they are right in the marketplace, with people who have come with their wallets to buy and haggle with you over the price, pinch your produce, and talk with you about how the weather affected the crops this year. So it's both a contrast and comparison to what I've collected with an Online Millionaire Plan. I'll let you know what I find. (Mostly, the basics are the same, just ramped up enormously - consider that you don't have to work that hard to find leads... Might be an interesting approach to getting stuff sold and has mailing lists as a routine.)
Community conversations seem to be the trail here. And Visitor Experience in a community translates to Quality of Life Issues in the real world. So all our work in marketing, especially social media, has incredible impact over in sociological fields - as well as sprituality. (But that's my metaphysical side talking...)