One way, although inelegant, would be to post a URL and see if I can delete it right away. If I can, that means it hasn't been posted prior to me posting. I'll

One way, although inelegant, would be to post a URL and see if I can delete it right away. If I can, that means it hasn't been posted prior to me posting. I'll have to detect the "0 minutes ago" and the delete link If I cannot delete, that means it already exists