Let's assume for a moment that one campaign to free someone in such situation would be successful. One person. From hundreds/thousands in one country. Probably tens of thousands throughout all oppresive countries. What would be the result? I'll tell you: the interwebs would proclaim it's own great success, that's a small leap but a giant step, blah blah. And happily in their chairs keep clicking, feeling like a hero while per every petition there is a thousand people keep being locked up and tortured and/or killed... Instead of exploring new ideas to act and engaging in more 'on the ground' action to help opressed people (probably the least but something practical you can do from home is keeping Tor running[1]), the web keeps signing up petitions. Taking part in such slacker campaigns is IMO a lose-lose situation, sorry.
[1] https://www.youtube.com/watch?v=GwMr8Xl7JMQ&feature=relm...
btw Tor worked with Avaaz on collecting donations for communication devices, yet: 1) it was a Tor initiative. 2) https://secure.avaaz.org/en/egypt_blackout/ "$25,197 raised so far. Help us get to $100,000". From the frontpage "14,921,795 members worldwide" with a minimum ammount of $15 it gives only about 1700 members who wanted to pay anything (and I can only guess that this number is much lower and there were bigger donations from single entities).