From guerilla marketing to guerilla start-ups?

43 Things is a pretty neat webite – it's a collaborative life goal setting tool. It's hard to explain so go play. The wonderfully named Robot Co-op built it with the help of the folks at 37 Signals who make the wonderful Basecamp. All well and good… then it emerged that, according to Salon, the Amazon refugees who had started the Robot Co-op were actually funded by Amazon.com. This is a bit like how A9.com came into the world but even more subtle. Robot Co-op have responded in their blog claiming the Amazon investment came late in the day. Who knows but it's very interesting what Amazon is up to. Their main site has stagnated design-wise but their other investments are blossoming. What are they up to?