I don't remember much innuendo on the sites I played as a child (club penguin, bin weevils) although I've got vague memories that the censoring was so severe you could learn swear words based off seemingly innocent words being blocked out of the chat. The bigger issue at that age was how exploitative some of those sites were with microtransactions and I can only imagine it's gotten worse with the current MMO's for kids.

There was one I briefly played as a child where one of the starting missions was growing something in a garden but if you were a free playing customer you had to plant in the public garden and wait 24 hours, so I'd come back the next day and find someone had stolen the stuff I'd grown and couldn't progress. It was a weird way to learn about wealth inequality and the privileges wealthier kids got at the age of seven.

There was another site advertised on one of the kids TV channels here when I was younger that encouraged kids to sign up and mark off the chores they'd completed and each chore you completed netted you a prize like a trip to Disneyland. What the ad didn't tell us at that young age was that your parents would have to pay for the prizes through the sites affiliate link. I think I was at least mature enough by that stage to understand we'd been had and it wasn't my parents fault but it's crazy that nearly twenty years later the internet's somehow gotten worse for exploiting kids for micro transactions.