If you look really closely, you'll see that in his inbox there are a number of emails where the names of the senders and recipients match the names of the staff who worked on the film.
There's also a scene where Bond and Vesper sail into Venice, where James resigns via an email sent to M. Audiences have already managed to identify Richard Branson at Miami airport, where he is frisked by security guards and Martin Campbell, the film's director whose character works at the same airport, has his neck broken in a short scene.
Bond films have always featured Easter eggs and Casino Royale is certainly no exception.