I do the same thing. I mostly inhabit Facebook, and once in a while I “adopt” a page to like and evangelize to the denizens there. Currently I’m working on “The New Civil Rights Movement”, a homosexualist agenda news aggregator.
I feel that the Church needs people like you, people willing to step into the breach and go where angels fear to tread. This includes the neglected atheist liberal secularist echo chambers where no self-respecting Catholic would be caught dead. Someone needs to be a “voice in the wilderness” to represent the Truth to people who have obviously heard many lies in their lifetimes.
It is unforgiving, and people can be heartless and vicious, and sometimes it feels like you’re not getting anywhere. But like any evangelization in hostile territory, sometimes there are glimmers of hope.
I consider every online contact, every in-person encounter, every meeting of the minds to be a fertile opportunity for evangelization. We should be proclaiming the Gospel to everyone we meet, especially the people who may be the most hostile to the message. We should be preaching without words, of course, in leading our lives righteously and blamelessly, but we should also be using words where necessary. Proclaim the kerygma every chance you get and it will eventually bear great fruit, if not in their hearts, in our own.