In a recent discussion, an_mo_user brought up the idea of a blog planet like Planet Debian, Planet Gnome. As promised in that thread, we have created such a Planet on http://www.mathblogging.org/planetmo (including a newsfeed).

For the moment, PlanetMO aggregates all blog posts (on blogs in our list) that use the tags 'mathoverflow', 'MO' or 'PlanetMO'. Since we would like to aggregate the full text, we will drop the first two tags in the future so that posts tagged 'mathoverflow' are not forced to appear there; in other words, the PlanetMO-tag is designed as an opt-in solution.

Besides the obvious appeal of looking up blog posts that mention MO, one motivation for the planet was to facilitate those discussions that are close to but not quite right for MO. A typical scenario would be a question closed as off topic. You might perfectly well agree that a question is off topic but you might nevertheless like to discuss it. To discuss it, you could write a short blog post and leave a link to your post as a comment to that question inviting people over to your place.

The advantage of such blog posts would be that no universal moderators are needed; instead each blogger acts as the local moderator. If the blog post is additionally tagged 'PlanetMO', you'll make it easy for people to find and join your discussion via PlanetMO even if they missed the initial question.

We hope this is can be a useful tool for the community here on MO. If you have any feedback (and it's off-topic for meta.MO ;) ) we would welcome your comments at our blog.