What's with all these evangelists?

Over the last little while I have been noticing the word evangelist pop up all over the place, particularly in reference to job descriptions in web2.0 companies. Probably the most obvious one is Vint Cerf who was recently hired by Google as "Chief Internet Evangelist". Is this a new meaning for the word "Evangelist"?

On my linguistics blog (A Word a While) I investigate.
See: AWAW: Evangelist

Tags: evangelist evangelism web2.0 languagechange linguistics awaw