I found this: http://www.dotcomicide.com/2005/05/did-googles-success-overwhelm-dmoz.html
Google themselves say
I think I know why they are picking up the DMOZ description but you're the SEO expert and I don't get out of bed for less than £200 an hour*. Hint: check competitors' sites who don't have the DMOZ description as the snippet and see what they do you don't.
* for clarity, joke, please don't ever offer editors money as it tends to elicit dramatic and unpleasant consequences.
Recently, in order to combat the "scraper site" phenomenon, Google has returned to using DMOZ descriptions in their SERPs again, probably because the DMOZ descriptions have a less keyword-laden snippets than Google's machine generated "ransom notes" do.
Google themselves say
Google's creation of snippets is completely automated and takes into account both the content of a page as well as references to it that appear on the web. We don't manually change sites' descriptions, but we're always working to make our snippets as relevant as possible.
I think I know why they are picking up the DMOZ description but you're the SEO expert and I don't get out of bed for less than £200 an hour*. Hint: check competitors' sites who don't have the DMOZ description as the snippet and see what they do you don't.
* for clarity, joke, please don't ever offer editors money as it tends to elicit dramatic and unpleasant consequences.