USPS Tracking - anybody know much about it?

So, I ordered something late Wednesday night. The guy said it was in stock and would be shipped tomorrow (Thursday, December 20th). I got a tracking number and when I type it into the USPS site all it says is that the electronic shipping information has been received. I've heard that this isn't really a tracking number, but it will just tell me if it has been delivered or not. Should I expect to not see any updates? I still haven't gotten it and it's been a week, but Christmas was on Tuesday, so I don't know.

I'm talking about priority mail too, if that matters.

A delivery confirmation won't show on the system until the item is scanned at delivery.

The DC is useful. I had the post office lose a package, but they were very willing to hunt for it since the DC showed it had been received the week before.

Theoretically with a delivery confirmation item a scan will appear from every office a package visits, including the original sending office and the regional hub. The holidays are slowing everything down though. At this point I would politely check with the sender to make sure the item was actually sent out. Although the system may say the item was going to be shipped that does not mean the sender actually put it into the mail stream immediately. Basically what you have now is confirmation that the sender said they intended to send the item, not that it was actually sent.