A WebmasterWorld thread poses an interesting question: there are a lot of useless submissions overwhelming the editors at DMOZ. Would adding nofollow stop these superfluous submissions and make the editors' lives easier?
For the most part, people think that it won't. Nofollow doesn't even stop spammers. (My other blog even gets comments submitted by spammers who explicitly add nofollow to the URL even though the blog software nofollows comments by default.)
But even so, why would DMOZ, which purports to be a quality directory, ever want to go the "we don't trust you" route of nofollow?
nofollow is for links the site owner does not trust.
At the moment a site link is added to DMOZ, the site clearly is trusted -- otherwise it would not be added. No obvious case there, either.
The bottom line is said by moderator pageoneresults: "Human Edited content should not require use of the nofollow attribute."
This statement, however, is disagreed upon by some users. What if a site that was included in DMOZ deteriorates in quality over time? Human edited content works for one time only unless there is a constant review of sites. Old links may lose trust.
Therefore, a few possible solutions are proposed: a system of checks and balances with multiple editors within a specific category and the ability for the average user to flag inappropriate results (for review by editors).
This post was composed on October 2nd and scheduled to go live on October 4th.