How do you find someones address online?

[raspyrock229]

Like, someone from Yahoo Answers or a social media site.

I've heard of stuff like this happening, and it even happened to someone I knew on a site called Spring.me

someone found out her address and told everyone.

i just dont want it to happen to me. how can I prevent it? should I use the deep web instead? if i use twitter, yahoo answers, youtube or anything through Tor, can people still find me if they stalk me?
yeah it was creepy. i've haven't asked how since i left for the summer. its just random people. we have our circle and stuff. it's not as popular as it was in 2009 and stuff.

but yeah, she hasn't returned since i guess.