Piwik # Open source web analytics – “Piwik is a downloadable, open source (GPL licensed) web analytics software program. It provides you with detailed reports on your website visitors: the search engines and keywords they used, the language they speak, your popular pages… and so much more.”
Scribe, by Facebook – “Scribe is a server for aggregating log data streamed in real time from a large number of servers. It is designed to be scalable, extensible without client-side modification, and robust to failure of the network or any specific machine.”