The domain system is a big under-the-hood improvement that has quietly gone live, but will start to be used. In short, the idea is that it is now very easy to create domains, which create sub-divisions of the full metaculus community (which we've started referring to as "Metaculus prime", or "MP"). The idea of a domain is:

• Each question has a set of domains associated with it, and it appears on those domains.

• Each user has a set of domains to which they have access, but all users have access to MP.

• Each domain has a top-level URL of form [domain].metaculus.com

• Each domain has its own leaderboard, and can have some other customizations, such as a few different look-and-feel options, different categories, etc.

• Users carry some of their information (levels, powers etc.) across domains but not all of it (with details TBD.)

The hope here is that domains can be used in a few different ways, e.g.,

• By a group or organization that wishes to create a set of questions private to that group, but optionally cross-post some of them to MP.

• By Metaculus or another group wishing to create a domain focusing in much greater detail on some particular issue, where some of the "top line" questions would be cross-posted to MP, but some finer-grained or more technical questions would be domain-specific.

We're currently in the process of integrating what was previously a private instance, ai.metaculus.com, into the domain system. So you'll probably start to see some cross-posted questions soon, and there will be discussion as to how to pin down some of the specifics of how domains will/should connect with MP. Feedback will be most welcome!