Director/adventurer/submarine captain James Cameron is embarking on his latest journey 140 characters at a time. If you're on Twitter you can follow him at @JimCameron. Does this mean we all have to start calling him "Jim" now? Because I'm so used to "James" I think that would be kind of hard to get used to.

The filmmaker is more prolific on Twitter than he is in Hollywood - he's been a tweeter for 2 hours and has already churned out 3 tweets - One introducing himself to Twitter, one complaining about press junkets, and one (of course) Ryan Seacrest re-tweet. Rumor has it that his next tweet will be completely under water. (MovieLine)