Does stamps.com reuse tracking numbers?
Either they do, or they've figured out how to ship things from the past.
Typical bureaucracy. They go and invent a time-altering shipping system, then delay the package for 2 years.
Maybe the default date of their system is set to when the system went live? ... I dunno.
If this were UPS or FedEx, I can think of a few ways this could happen. Wrong system dates on the shipping terminals are not double-checked when sent in. Also, they reuse tracking numbers. Sometimes when you get a recently reused number, and not all of the information is available or supplied, the old information lives on in those unsupplied fields.
Yesterday afternoon it showed the correct ship date (February 8, 2011), but this morning it's back to December 4. And why reuse numbers? With that many digits available, there's enough for 900 trillion unique tracking numbers for every person on the planet. Probably more. It's early and I haven't finished my coffee yet, so I didn't think about it too hard. It's possible the shipping info is somehow encoded into the tracking number. It's really not a big deal unless I don't get my mail, it's just strange.