overnight activist

A person who, upon seeing a political message on a social networking site, instantly becomes a die-hard supporter despite knowing nothing about the subject.

Jackie -OMG, I just saw KONY2012. Save the Children!!!!
Brenda -OMG me too. It's so sad that this is happening in Uganda.
Informed Individual- You know this has been happening 26 years and that the Ugandan gov did the same thing to get in power... overnight activists