Revival is something sent from God and involves a degree of spontaneity. It is not contrived and is not man-centered. Revivalism is something that is often manipulative, forced and contrived. Iain Murray's book, Revivals and Revivalism , is central to understanding the difference between the two key terms. Murray reviews all the major revivals in American history as he presents his argument.
True revival involves primarily the confronting with and the repenting from sin.
But I think that true revival will come through searing, heart-piercing, convicting preaching where people are driven to their knees to repent. Each one of us is going need to evaluate whether what is happening in Brownsville is genuine revival. In many ways we cannot definitively conclude whether this is revival or not. We need the perspective of history. Every genuine revival has produced genuine life change, that results in significant social and cultural change, that also results in outreach in missions.