Last Updated: June 2nd, 2014
Back on Halloween, Google promised that proprietary binaries and factory images for the Nexus 4, Nexus 7, and Nexus 10 would arrive shortly after devices received their OTA updates. Even though some OTAs haven't even rolled out yet, as of a few minutes ago, all modern Nexus devices now have Android 4.4 KRT16O factory images and drivers available for download.
This means you can flash stock Android 4.4 onto any supported device, even if an OTA either wasn't available yet or wouldn't work for some reason.
Last Updated: November 3rd, 2013
Advertising revenue is a huge part of doing business in the mobile apps space for a large number of developers. As such, from that practice have emerged methods to send advertisers information about you to better serve appropriate ads. Oftentimes, the way your advertising "profile" is specifically identified is less than ideal from a security standpoint. Many apps use your phone's IMEI - a potentially personally-identifying number - as your advertising identification number because every modern smartphone has one.