I would describe both Playboy and Penthouse as primarily pornography. As such, they were both wildly popular in the 1970s and early 1980s.
Omni was not that. I had a subscription to Omni from the first issue in 1978 until about 1983. Pop science, science fiction, fantasy art, interviews and features on space exploration policy... and junk science, UFOs, psychic powers, cults. News of the wierd.
Either that got ninja-edited in the 8 minutes since you posted that comment, or you misread that paragraph.
defrost•1h ago
* https://en.wikipedia.org/wiki/Small-C
* https://github.com/trcwm/smallc_v1