I think social media can be the most addictive thing on the internet. Porn is really the most addictive thing on the internet out of all things. If you really don't watch how much time you spend on the net you can easily over do it. I really had to limit my time on social media myself. There are ways to become addicted to the internet.
It's really easy to spend the majority of our lives online. The internet makes life so much easier and presents a whole new world of opportunities that we never had in the BC (before computers) years. I would only say there's a problem if the time you spend online is interfering with your day-to-day responsibilites.