Hewlett-Packard Co. may be the world's largest technology company, but the superlative that better suits it these days is Provider of the World's Strangest Corporate Drama. For two weeks, almost every day has brought revelations of questionable tactics that HP investigators used this year and last to root out who had been describing boardroom deliberations to the media. Corporate intelligence is an old and frequently practiced art, but HP's efforts feel more Watergate than Wall Street. Not only did investigators impersonate board members, employees and journalists to obtain their phone records, but according to multiple reports, they also surveilled an...