The original 3rd-party video game maker for the Atari 2600, Activision apparently saw the writing on the wall in 1983. That was the year they made their move from consoles onto computer platforms, such as porting Kaboom! and River Raid to the Atari 8-bit XL line as seen in this ad. Moving to computer platforms helped the storied company survive the big video game crash of 1983-84, allowing them to become one of the biggest video game companies still around today.
For more information on Activision and the Atari VCS, consult your local Dot Eaters entry.