There is some publicly available information which will help you find out about timings though. If you're really keen, you could look at the (more or less) weekly
RDF dumps and see when a site first appears. Or if it was a while ago archive.org may have old copies of the category page stored which you could look at. For more recent changes the google cache may help.
(BTW: it's better to think of them as suggestions, not submissions. No site is guaranteed a listing, and since we're all volunteers we can't even guarantee any timescale for review of public suggestions.)