Active liberal churches and movements have pretty much majored on social action and real help for poor people in developing countries. I think what Andy says about Evangelicals getting their act together in recent decades holds a substantial amount of truth.  There is a difference that I perceive quite often (not always), in that liberal social action tends to come with few strings attached, the emphasis being on plain help. Evangelicals more often use their works as a sort of vehicle for proselytisation, and this, I think can get in the way of the good things they do and can pervert the compassionate motivations they have.  As I say, Evangelical action cannot all be lumped in the same category (nor can liberal action) and for that we can be grateful.