U2's appeal to Christians and non-Christians

Joe Hebert, on atu2, posted this link to some good conversation, click the word "here" to enter it:

In this look at what is going on in the forum, I wanted to draw special attention to one of the best topics I have come across in a very long time. In spite of being a band that is not shy about touching on religious topics in their music, U2 still is able to maintain a sizeable portion of its fan base that does not share those same beliefs. How do they do that and why are non-Christians fans of the band as well? You can find thoughts on this here.