How can I prevent internet addiction? I'm scared...

Find yourself some other hobbies which include outdoor activities or just activities outside your house. Try doing stuff like in the old days like using the phone , or the newspapers going to a library that for sure will help reduce time on the Internet.

I don't thin that you really need to worry about it. I think that everything can be addictive, I know people who are addicted to sports, drugs, sex, shopping, and so on. In my opinion some people are more pron to addiction then others, and many times people who tend to have addictions switch from one to another - I don't think the existence of internet in our world changes the amount of addicts in the population - it's just that some of the people who were addicted to TV or to computer games or to gambling tend to move to being addicted to the internet.

If you feel that you are pron to addictions, then I think you should see a therapist and try to understand the source of your addict personality and how to deal with the temptation. If you are just a common user that find himself use the internet more and more - I don't think it's addiction, just another way of communication.  

You need to learn self control and to find activities away from the computer.  It is not easy because society wants to make you think that the world runs through the Internet.

 For more help check out this Internet Addiction Resource.

For a condition that some don’t believe even exists, internet addiction goes by many names—net compulsions, internet addiction disorder, compulsive surfing, web dependency—none of which holds any official status. In fact, the contrary is true, as no credible medical association has been willing to embrace the condition.

Either way, one might safely regard the term as a catch-all holding company of sorts; a folder with no true meaning of its own, but containing any number of files, or web-related activities which have, according to the scant documentation available, shown some capacity to cause problems in one’s life. One widely quoted estimate suggests that between 5-10% of people online are "web dependent."