Most of this stuff used to spread word to mouth. It still does.
'Funny people' on Reddit still post links to NSFW in SFW spaces. Googling something angsty can be interpreted as a search for XXX. Twitter isn't exactly safe either, and can teach a few people NSFW words to get curious about. R34, DeviantArt etc. are all alive, and anything hentai related is far more prominent and mainstream than before. People interact on these sites and suggest enough to instill curiosities.
It's not as on the nose as old flash game sites showing a highlighted "18+" with a shitty age verification or a random ad sending them into the rabbit hole, but it's still very much there.
'Funny people' on Reddit still post links to NSFW in SFW spaces. Googling something angsty can be interpreted as a search for XXX. Twitter isn't exactly safe either, and can teach a few people NSFW words to get curious about. R34, DeviantArt etc. are all alive, and anything hentai related is far more prominent and mainstream than before. People interact on these sites and suggest enough to instill curiosities.
It's not as on the nose as old flash game sites showing a highlighted "18+" with a shitty age verification or a random ad sending them into the rabbit hole, but it's still very much there.