In the universe of blogs and other syndicated content, a planet is a service that aggregates a specific set of blogs, usually all relevant to a particular community, so that one may easily follow conversations (or at least blogged updates) in the community or drop in and see what is happening in a community without having to visit many individual blogs (and having to figure out which ones to visit).
Planet Debian and Planet GNOME were the first two planets. Now a planet aggregator is a well established communications channel for many large free software communities, complementing mailing lists, IRC, wikis, and individual and project blogs. Planet Mozilla is another good example.
We’ve been syndicating CC jurisdiction project blogs on the CC home page for a while. Now you can see more and subscribe at planet.creativecommons.org/jurisdictions/. Or visit the Planet Creative Commons home page to get this blog, CC jurisdiction blogs, and various CC community blogs all at one time.
You can read about the software that runs the Planet on the CC wiki, including CC engineer Nathan Kinkade’s plugin to read syndicated license information.