Forum Moderators: open
The RDF dump, which is served to downstream users, has been last updated on May 31, 2003
The internal search db is updated now and then. Once a week is highly optimistic; once a month is typical.
Here's a few related discussions:
Listed in dmoz but not coming up in search [webmasterworld.com]
How long for DMOZ data to move to Google? [webmasterworld.com]
DMOZ RDF push [webmasterworld.com]
DMOZ RDF Updated! [webmasterworld.com]
Google Directory and New RDF Dump [webmasterworld.com]
Google Directory update [webmasterworld.com]
A site search with "dmoz update", "odp update", or "rdf update" may turn up some more information that you're looking for.
Editors throughout the world are adding and deleting sites and modifying descriptions right now. The category pages reflect these changes, usually within an hour of the change. So at the category level, the ODP is ever-changing.
The other reply answered how often the search database and RDF database are updated. To summarize:
category pages: constantly
RDF database: approximately weekly
search database: approximately monthly
I suspect the latter two frequencies will become more consistent once all the ODP upgrades are complete.
-- Rich