On April 1, Jonathan Schwartz, president of Sun Microsystems, had a disappointing message for readers of his web log. "The downside of being an officer of a public corporation is that it's very difficult to write a good April Fools' blog without feeling the need for serious engagement from the corporate legal team," he wrote.

That escapsulated the difficulty for the generation of corporate leaders now trying to communicate with employees and others - from competitors to suppliers and analysts - through blogs. Mr Schwartz and Bob Lutz, vice-chairman of General Motors, are the most prominent examples of those engaging with the outside world directly rather than relying on speeches and official announcements.