'Evangelist' is a word that increasingly crops up in job ads. To be an 'evangelist', literally, is to be one of the four apostles, or a travelling preacher spreading the word of the Lord. Its ultimate source is two Greek words meaning 'good' and 'announce'. But it is being extended to those whose job is to persuade customers or colleagues of the value of a product or service, especially in the world of technology. An ad for a Unix systems administrator for Google, for instance, suggests the successful candidate will be a 'technical evangelist'. Other recent ads seek an 'evangelist of user experience' and a 'compliance evangelist'. The source is the US, where people even have the word on their business cards. This seems to have started with a man called Mike Boich at Apple Computer. The word was popularised at the firm, perhaps as an ironic comment on its status as a sort of religious sect. Apple evangelists set out to make converts and encourage the faithful. Getting your customers to do the selling is called 'evangelism marketing', and it has a big advantage: it's free. Hallelujah to that.