That would be Atari spelt with a capital C that looks like a chicken mouth.
This person is not necessarily an idiot. It could also be to expand the number of search hits. Amiga will get so many hits; Atari brings in so many extra. Then hopefully some computer enthusiast comes along looking for Atari, realises that this is not it, but thinks "hey, thet's some pretty nice stuff, and a good deal."
I don't approve of such behaviour, but it does work. Of course, adding Commodore would have expanded things even further, but what the heck would a Commodore Atari be?
Hans