The EtherPad collaboration-enabled online system is now open source. Cool. Google bought the company, the developers are joining the Wave team, and their product is now released under the Apache 2 license.

Be sure to follow the instructions (failing to set the environment variable for the path to a MySQL client JAR file produces a strange "cp -f" error that has hung up a few people trying to build the system, as reported on Hacker News). It only took about 15 minutes to download the source and build the system - simple enough.

After running the system and trying it, I used IntelliJ 9 to set up a project (choose project from existing source, main directory etherpad/trunk) and I am spending some time perusing the Scala and JavaScript code. Really nice looking code base, and reading through the Scala code will be an education. My JavaScript skills are a little weak, but I might still take a careful look at the JavaScript code to understand how they used Comet.