I found myself falling into a trap with wanting to respond with the same mocking tone I was getting on an atheist website. I had to step back, ask God how to be a witness, and the words just fell into place. I thank my Saviour from saving me from myself.
Our God is pretty wonderful like that. Even when they mock Jesus, we have to try not to mock back. I think everyone has been in a scenario like that, Christian, Muslim, Jew, atheist and so on alike. One may just want to type, "BIGOT, BIGOT, BIGOT!", and even that is too much. I love this quote by Einstein, "Everybody is a genius. But if you judge a fish by its ability to climb a tree, it will live its whole life believing that it is stupid."