There was a recent post on the Shopify eCommerce forums where someone asked how to change the sort order of products in the Admin (not the storefront). I can actually see the use case for this but thankfully a simple url change can make it happen.
The Shopify Product API contains a order property to let you sort list. Since the Admin uses the API we can use that same property and get the same result. This means instead of a url like this:
You would use one like this:
Change the asc to desc if you want to sort in the other direction for the created at date.