Friends, neighbors and classmates recall a troubled Jared Lee Loughner, prone to angry outbursts and anti-social behavior. A panel of mental health experts discusses the missed signals and challenges of cases like Loughner's.

Cable giant Comcast bought a majority stake in NBC Universal in a deal valued at approximately $30 billion. Jeffrey Browns talks to business journalists for more on the merger.

Advertisers and employers are moving to take advantage of social networking Web sites, such as MySpace and Facebook, as the sites draw hefty numbers of users. Judy Woodruff reports on the phenomenon in the first part of a series on…