Today is 10/10, which makes it Duopoly Day and thus a good time to indulge my obsession with Google/Facebook and walled garden vendors in general. Let’s start with news from ClickZ that Amazon advertisers are more likely to expand their spend on Amazon than Google or Facebook advertisers on those platforms. The key factor is that Amazon’s detailed product search information is a super-effective targeting tool. There’s plenty of room for growth: just 15% of marketers feel they’re using Amazon Marketing Services to its full potential. Lots of other interesting stuff.