We've all seen the lists of celebrities on Twitter, and the microblogging service makes it simple to keep tabs on your favorite actors, musicians and miscellaneous famous faces.

This slideshow examines the plethora of ways celebrities use Twitter. From creating spontaneous buzz, like Shaquille O'Neal challenging Lance Armstrong in a race or Lenny Kravitz' self-leaked nude photos, to launching the next iteration of stardom, like Ashton Kutcher and Sean Combs, celebrities Twitter for a wide number of reasons.