Over the past couple of months, I have used mostly FaceBook to spread the information about the planned drive. I have reached many people by using this format of interaction with people that I might get to meet along the way during the drive. 
It would seem that unless cancer directly affects a person, they are not interested in a cause or the intended message about cancer.
There are however a couple of support groups where people can make postings and hope to get an answer from another person across the world. But I have found that a more personal support group would be a lot better because at the group meetings, your questions will be answered by people that have already experienced what you are going through right now and not tomorrow.
The un-personal nature of using Social Media for your support group is great to start with, but ensures that you set up regular meetings with those that you discuss your experiences with. 
Then there are the chat rooms. There are some individuals that go to chat rooms to mislead others for personal gain. Be very careful when accepting a new member to the chat room. Read carefully and decide for yourself if the individual that you are chatting with really experienced the loss of a loved one due to cancer, or are suffering from cancer. Do not accept any medical miracle cure advice over a chat room as if you are dealing with cancer yourself.
Use Social Media wisely, but always be careful.