He's talking about it being constant. If it's just during gaming or whatever that's fine, for laptops seeing how they have terrible cooling, for desktops it's a bit worrying.
Well if you game daily like most people, 80 C is very bad temp to hit during games. In a typical day your cpu shouldn't get above 70 C. If you're doing something extra on one particular day, it can get higher but you really want to avoid that. Like dkamm said:
Constantly running hot will shorten its lifespan.
Under 70 is safe, anything above isn't guaranteed to be good. The max temp is 105 (or whatever's in the BIOS), but that's pretty much only there to do shut stuff down if you're having a small nuclear reactor meltdown.