Katie Couric to leave 'Evening News'

And just like that, it's over: Katie Couric will leave as anchor of "Evening News" at the end of May, ending an experiment that was supposed to reverse a viewer decline, but which instead threatened to accelerate one.

Couric chose the unusual venue of People.com to make her decision public shortly before 3 p.m. Tuesday, saying in part, "I have decided to step down from the 'CBS Evening News' . . . but I am excited about the future."

Later appearing on PBS' "Tavis Smiley" for a pre-scheduled interview promoting her new book, "The Best Advice I Ever Got," Couric said the job has been "a pretty confining venue [and] I'm looking forward to do what I do best . . . having more extended conversations."

She's expected to launch a syndicated talk show.

Couric joined the storied CBS broadcast on Sept. 5, 2006, succeeding Bob Schieffer, who had added viewers during his brief tenure.

The Couric-helmed program was initially designed to fit her strengths -- with extended in-show interviews, and lead stories that didn't always reflect the day's top news -- but viewers quickly rejected that format and so did CBS.

However, Sandor Polster, a longtime editor for both "Evening News" and "NBC Nightly News," now retired, said Tuesday, "Katie is a competent journalist, but had too much a history of being a lighter personality in the morning, and it did not translate to the evening. It's that simple."

Viewership declined during her tenure -- tying a 20-year low last summer (4.9 million) -- though most recent Nielsen figures had "Evening News" with 5.7 million viewers, to 8.4 million for "Nightly News" and 7.7 million for ABC's "World News."