Social media is one of the most effective tools used by a majority of people across the world. You can use it however you would like to. Many people have abused social media and have hurt others. Some people declare their faith with social media in ways that benefit those around them. From personal experience I have seen the positive and negative effects social media has on any human being.
When I think of defending my faith on social media, I think of posting the largest verse in the Bible to help support my standings. To be honest, that's a silly idea for many reasons, but I will narrow it down to say the best way to defend your faith, that is the Christian faith, is to say it like you would in person. Sometimes people think that because there is a machine in front of them they are safe to say whatever they put on the web. The idea behind social media is to have any person, mostly your friends, see what is happening in your life. It can be used as a great influential tool if they begin to see some of what you believe in and so on.
So I really haven't explained how social media helps you defend your faith, but I kind of turned to how social media can be used to gather support for the belief that you have. It's not about winning numbers, but these days we ought to put a little "Jesus in the jpegs" and display our faith to others. To sum it all up, we can use social media in whichever way we would like, but in the end it is up to others in what they decide to believe.