Last month, Twitter fans received a shock when a study revealed that exactly zero percent of its 1,900 participants would consider paying for the service. Last night, film critic Roger Ebert challenged those findings, showing that a significant number of his followers feel differently. About 4,000 of Ebert's followers responded to a one-question survey he created, and out of that group, 19.4 percent indicated they'd be willing to pay for Twitter.