Interesting, this article from March mentions the kitchen uses of the magnetic connector. I've loooked for a patent number but I'm unable to locate one. The closest I've come is a Chinese trademark for MagSafe, which isn't very close at all.

Despite the current uses in Kitchen appliances, I assume Apple would still have patent rights if the original patent is outdated and/or didn't extend to personal computing devices. I assume, this is why patent descriptions -- and pictures-- are extremely vague.

There are dozens of connectors similar to the iPod connector, but a manufacturer still has to pay Apple a license fee to use the iPod's connector. The same would apply to Apple's unique Magsafe connector. If your percolator's connector works, go for it (I wouldn't recommend trying though).

The 4 contacts aren't just power btw. The connector on my new MacBook Pro's adapter failed and the symptoms were that the computer simply didn't recognize that it wasn't charging. The result was 100% charge indicated until the computer shut down when the battery went dead.