I think that we could at least create an organised pressure group.
The key with getting a good response from online forums, with respect to getting letters sent, petitions signed etc. Is that you are already a respected member of that forum. When I was doing the Thornborough petition with a vengance, I tried to become a respected member of some 50+ forums overnight! with obvious response levels.
It occurred to me at that time that if a small group of us were a bit more organised - targetting larger forums, splitting these between us, and also opperating a buddy system for moral support, then we could provide a significant political force to any issue that we felt important enough.
Often the local people feel powerless and thereofre do not bother, providing them with hundreds of messages of support, almost overnight often gives them the boost they need. For example, prior to the latest bit of the Thornborough campaign, we understood that in Thornborough, only about 40-50% of locals supported our aims. The written petition, which is going door to door, currently has a 98% sign up rate for all households within a five mile radius of Thornborough, and every day this radius is expanding, we currently estimate the written petition has close on to two thousand signatures. The fact that people from as far afield as Brazil, USA and Australia have bothered to sign the online petition has added a lot of credibility to the local petition - people really do see this as an international issue rather than some tinpot set of locals looking to cause a storm in a teacup.
That's what I think is a simple first step - let's get organised!