Twitter Inc (NYSE:TWTR) may have nearly 50 million monthly users in the U.S., but according to the chart below from Pew Research Poll a large percent of U.S. adults are not Twitter user. I just think twitter is the latest “it” factor! You never know when that cool factor will wear off like Myspace. A large percent of Twitter users are young people. Young people are unpredictable; they are always jumping on or off the latest bandwagon. In order for Twitter to survive, they can't rely solely on young people.