Four short links: 17 February 2012
- How Target Figured Out A Teen Girl Was Pregnant Before Her Father Did — predictive analytics moves faster than family communications. (via Sara Winge)
- Web Caching Tutorial — explanation of the technical ins and outs of web caching.
- Gatekeeper — Apple’s new app security technology for Mac OS X. Identity, general purpose computing, security, and third-party kill switches all in the one technology. (via John Gruber)