Fingerprinting Cameras through Sensor Noise – Arvind shows how unique the noise pattern that your camera embeds in every photo you take really is. It's as identifiable as a thumb-print, and with high resolution pictures available from many sources associated with your real name, makes it theoretically possible to match up photos you've tried to take anonymously. The one saving grace is that compression removes a lot of that unseen uniqueness, but it looks like you'd need to go down to 60 quality on JPEG to be sure.
Multiplicative Microdata Noise for Privacy - Noise isn't always bad though. I'm fascinated by the ideas of adding it to prevent reverse-engineering of sensitive information from data releases. I bet it's tough to get right though, I'd love to set Arvind or some of the Kaggle team loose to see how solid the protection really is.
requirejs – He also showed me this solution for proper module loading in JS. The syntax is a bit funky, and I know we'll still want to compile and minify for production, but it's still a good tool to have in your kit.
TeleHash – An intriguingly generic way of connecting machines together in a peer-to-peer way using distributed hash tables. Maybe it's just my exposure to them as I do more Cassandra work, but DHTs seem to be popping up all over the place.