Broad perceptions become so embedded in the collective psyche that they are very hard to shift, but one that finally bit the dust last week was that of IBM as a bellwether of the US – and world – economy and a shining example of all that is brightest and best in the US industrial landscape: the fact that the professionals now recognise IBM as company that makes most of its money in a mature, low-growth business (mainframes), and is not very good at the newest and fastest growing sectors of the industry is exemplified that while IBM stock carried on down after its profit warning, closing $2.75 further down at $108.875 on Thursday, the market as a whole was very chirpy, with the Dow putting on 21.85 points.