NOTE: As of 6/21/2012, the source code has moved to the Chromium repository. The instructions in the wiki have been updated.
The RLZ project is a library for grouping promotion event signals and anonymous user cohorts.
Client applications with the RLZ library can use explicit cohort tagging to manage promotion analysis. A client application with a particular tag can transmit that tag as it chooses for payments and analysis purposes. As an example, the RLZ parameter "rlz=1T4AAAA_enUS202" indicates the client application is Toolbar version 4, distributed with AAAA software bundle, English version, to a US user in December 2006. This empowers computation of metrics broken down into useful dimensions.