>>718634193 (OP)
the literal, whole, entire internet, and the way we approach basically every single game, and game design, and the way we treat eachother, etc. it is impossible to say "it just affected one genre", it is literally an entire paradigm shift
back in the day people made games they thought were cool, and people who thought games were cool played them, and just did whatever on them. the concept of "optimizing xp/hour" did not exist to the average person. the idea of a "proper build" did not exist to the average person. people would (sometimes) read the tooltips and just click around on random shit. and nobody cared. there was no "dps meters", there was no "you need to have 100 cs by 10 minutes", there was none of that shit
now, every single online game has a data aggregate site. every single single player game has the IGN guide / youtube walkthrough posted before it comes out. there is no sense of mystery. there is no unknown. there is no "i wonder if this is good", you can simply search it up online and already know