Forum Moderators: open
It never did. Or let's say there is no generally accepted evidence that it did. Google has stated over and over that it treats a link from Dmoz in exactly the same way as any other link.
Because lots of other sites use copies of the Open Directory, one Dmoz link generates a lot of other links. Naturally that gives a boost to PR.
But Dmoz is not the only link that spawns offspring. Yahoo has versions of its directory for different countries. So one link in Yahoo can yield a bunch of backlinks.