Consumer Heterogeneity and Paid Search Effectiveness: A Large Scale Field Experiment (PDF) — We ﬁnd that new and infrequent users are positively inﬂuenced by ads but that existing loyal users whose purchasing behavior is not inﬂuenced by paid search account for most of the advertising expenses, resulting in average returns that are negative. We discuss substitution to other channels and implications for advertising decisions in large ﬁrms. eBay-commissioned research, so salt to taste. (via Guardian)
The Human Microbiome 101 (SlideShare) — SciFoo alum Jonathan Eisen’s talk. Informative, but super-notable for “complexity is astonishing, massive risk for false positive associations”. Remember this the next time your Big Data Scientist (aka kid with R) tells you one surprising variable predicts 66% of anything. I wish I had the audio from this talk!