Okay kiddo, imagine online service provider law as a set of rules that people who run websites have to follow. Just like how you have to follow rules at school or at home, website owners have rules they have to follow too.
One of the most important rules is that online service providers are not responsible for what people do on their website. For example, if someone posts something bad or illegal on a website, the website owner can't get in trouble for it. It's like if you invited a friend over to play with your toys, but they broke something, you can't get punished for what your friend did.
There are a few exceptions to this rule, though. If the website owner knows about something bad happening on their website and doesn't do anything to stop it, or if they encourage people to post bad things, then they can get in trouble. It's kind of like if you saw your friend breaking your toys and you didn't tell your mom or dad, you might get in trouble for not stopping your friend.
Another rule is that online service providers have to protect people's privacy. That means they can't share people's personal information with other people without their permission. It's like how you wouldn't want someone to tell everyone your secrets or where you live.
Overall, online service provider law is meant to keep people safe on the internet and make sure that websites are following the rules.