If signing an online petition is all that you ever do about serious social, environmental, economic or political issues, then neither do you help change the current situation that you are complaining about, nor does it make any real difference.
It is even worse if you have signed those petitions because some of your friends have done the same.
Try to get to the root of the cause, try to understand it, and if you do understand the issue, raise your voice out louder. May be join the larger protests?
If you do not want to be on the streets or be public about your views, why not stay in your comfort zone and try devising actual solutions to these issues? Like raising awareness, instead of just complaining, may be by writing about it, or talking about it to your friends who do not understand the matter in concern very well. Even better, if you are a technologist, maybe you can come up with technology-driven fixes for those issues that can be fixed with better technology.
Why stay inside a sound-proof glass house and try shouting occasionally at the world outside? No one will hear you. They will just see you make weird gestures.
Why not push your limits and try to make a difference?