Increasingly, Facebook and Twitter are overlapping, setting the stage for one of the biggest Silicon Valley rivalries over the next few years.

Both companies want to play a major role in how people communicate online, a potentially lucrative business but one that is hardly settled given the ever-shifting online landscape...

A survey released last month by the Pew Internet Project found that 11 percent of online adults have used Twitter, Facebook or other services to post messages, highlighting the increasing popularity of what's officially known as status updates. Pew found that 4 percent of respondents had posted the day prior to being asked.