Site was removed from DMOZ, info on why?

I had a site listed on DMOZ for some time. The site was removed about 1-2 years ago and I have no idea why.

I found another website that was using the same data as my site had, is it possible that it was treated as duplicate content? The site mentioned is no longer around.

I'd be happy to provide the URL, and category I was listed under, but I believe listing URL's is against the terms...

Any help would greatly be appreciated.

Lack of unique content on a site is certainly a reason for removing its listing. (In fact, it's ultimately the only reason.)

If the site's content is now "unique" (which doesn't mean "original [wording]", the uniqueness is of the information contained), then you can certainly suggest it. In the normal course of events, it would be reviewed, just as if it had never been listed before (because sites have been known to change owners and content).