Rambo actor Sylvester Stallone, who is on Twitter, recently stated that using the site for publicity of a film is acceptable, but that he doesn't feel he should use it to share his personal feelings with fans.
He stated that he used to tweet regularly, but that he finds it an act of futility and a star never really makes any impact by sharing his personal thoughts on the site. The actor also added that Twitter might be a great tool for promotions, but not for small talk.