Adam was mostly interesting in terms of marketing. The Atari 5200 was based on the 400/800 computer, but was intentionally made incompatible. Meanwhile, Coleco

Adam was mostly interesting in terms of marketing. The Atari 5200 was based on the 400/800 computer, but was intentionally made incompatible. Meanwhile, Coleco heavily advertised the 'computer expansion unit (coming soon)' as a way to upgrade your ColecoVision to a real computer. But by the time Adam finally shipped, the weirdo data cassettes and price made it pretty unappealing, and the ColecoVision was practically dead at that point anyway.