Over a year ago, I did a two part series in which I said that evangelicalism and fundamentalism were teeming with ecstatic and demonic influence (part one, part two). This was a major issue at Corinth, so it's been around for a long time. After all, we do wrestle against spiritual wickedness. Confusing spirituality is a big tool of Satan. He wants people to think they're doing fine when they're not. They're the ones who will say "Lord, Lord" on judgment day (Matthew 7:21-23).
John Piper was recently down speaking at Passion 2013 (you can watch the "worship" time here, definite disclaimer for the night club, but it is the worship of Passion 2013). Piper is a big favorite of evangelicals and many fundamentalists. Mark Dever, a real fav of fundamentalists as well, has pushed for men like Lecrae, the rapper here who is leading the "worship"). Does this really seem legitimate to seriously professing believers? Thousands went and said it was a real spiritual time for them. The people at Corinth also saw their ecstasy as spiritual. And it is spiritual in one way. Demonic. It isn't the Holy Spirit, that is clear. You can judge that. Don't be afraid to judge that.
If there is any doubt about whether Piper is a Charismatic, watch the following. It will clear it up. He doesn't understand 1 Corinthians, for sure.