Advantage and disvantage of internet and social networks

There are some great things about the internet. There is a lot of information,so teens can use the web to help them with their schoolwork.''Chatting'' online is much cheaper than using mobile phones, so they can save money . they can also communicate with people all over the world.
But the internet  can also be dangerous.Since it is open to everyone, teens can see not only good,educational websites,but also bad ones.Because of all the attractive games on the internet, some teens become addicted to it. They can't stop playing.