The residents of Silicon Valley are more confused than usual after a billboard campaign by the National Multiple Sclerosis Society of America used this line in an ad slogan. "MS: It's not a software company." Exploiting the fame of a certain company to draw attention to an altogether worthier cause. Requests to comment on the campaign have been met by a surly silence by Microsoft which doesn' t relish the association of ideas, but is painfully aware that it can' t afford to appear insensitive over such an issue. Seasoned IT professionals will have no trouble telling the two MS's apart: One is a debilitating and surprisingly widespread affliction that renders the sufferer barely able to perform the simplest task. The other is a disease.