One thing a multi-site scraping aggregator could do would be detect listings that have been re-posted with just a date change, and show the real amount of time

One thing a multi-site scraping aggregator could do would be detect listings that have been re-posted with just a date change, and show the real amount of time the ad has been up, alongside how long it's been most recently refreshed. It would be interesting to search for ads that were posted a long time ago and are still unfilled. And it would be intersting to see how that add "posted 12 hours ago" is the same one that was posted 6 months ago and is currently being posted by 5 different recruiters with almost identical wording apart from their boilerplate. And it would also be interesting to see the different salaries/ranges that are mentioned on different copies of the same ad. I've noticed different recruiters sometimes post the same ad, but with a different salary ceiling. Guess which number I'd like to have when negotiating... And if I see a job whose salary has been creeping up for a few months, that's an interesting trend too.