It isn't often that every time I ask a question in a subject I get reminded how little I know about it. Thanks for bearing with me. If every Mac made since OS8 debuted has an Ethernet card, those Macs de facto have an machine dependent ID. How often do people replace their Ethernet hardware? As for USB... USB seems to be the perfect platform for small, portable dongles, and even wheezers like my G4/USB souped-up 7500 support it. The remaining PCI Mac users out there without native USB would have to spend maybe $70 for a USB+FireWire card, something they probably should have done already. One of the most expensive PC applications I've ever had the pleasure of using (Wilcom's Sirius embroidery digitizing suite, $30K US) uses a card dongle and the traveling salesmen demonstrating it on laptops use a USB dongle. [My educated guess is that buried in a legitimate software-critical system interrupt, something sends an unobvious high-level request passed through other legitimate routines eventually to the dongle, the dongle belches back a code, the code is eventually factored into a return address for one of several common subroutines, without which the software will have an inaccurate return address and crash. Hackers are then tasked with deconstructing miles of assembly code in several libraries to figure out the paper trail back to the dongle, black-box its algorithm and substitute their own software mechanism. Of course, I'm wildly speculating here with a novelist's imagination, not a coder's.] Am I being incredibly naive to assume that any future MacOS compatibility issue with USB dongles would also likely apply to a large portion of supported USB hardware (i.e., have to be resolved by either Apple or the vendor) and thereby render the taboo irrelevant?