With the Gregorian system heavily entrenched in the west and increasingly accepted across the world 'A.D.', which stands for Anno Domini ('The Year Of Our Lord', a reference to Jesus, the central figure in Christianity) is increasingly seen as inappropriate given the majority who have different, if any, 'lords'. Christians are able to retain their reference to Jesus by substituting Christian for Common.
By using loose and non-thematic terms C.E. has the benefit of not being wrong. When Anno Domini is applied to the Gregorian calendar, it refers to the number of years since Jesus' birth, beginning in 1 A.D. (Jesus having been born the previous year as there is no year 0). Unfortunately, the historical Jesus was born earlier than this, perhaps 4-7 years earlier, making the true A.D. at least 2009 not 2005.
