Why are my posts and other items on the internet showing up as a hit on the internet searches published?

[SB]

Basically, I am not a "computer savvy" type of user. My generation did not have the internet "70's/80's" so I was shocked to find my personal opinions and "Posts" show up as published information on the internet! Why? So, I signed up to a "Brand-New" page "Grind TV Yahoo" and used the same name but with an obscure age, on purpose, which was "13" just to see what it would do/say now? Well, low and behold, that too was published! If I was indeed "13" wouldn't that be illegal? Because that would have clearly denoted that I was a child and underage! So, what is happening and who/what is publishing my "User name/Avatar" on the internet? It seems as if they have been "Cached"? Whatever that means? Who does that? Why? How can it be stopped? Isn't it a violation of my Privacy Rights? Please let me know-Thanks!