Dollar-amount consumption levels by sector for bottom, middle, and top quintiles by income. Consumption adoptions rates (s-curves) by invention over time. VCR is to date the most quickly adopted technology ever, beating out cell phones.
I’ve gotta say a big thank you to the folks at Google for making a big contribution to making XFN and, to a lesser extent, FOAF more useful. This is in the long-run more interesting than all the vampires and zombies crap on Facebook put together.