Colbert's challenge in following Letterman

Wow -  that was fast.

On Thursday, CBS announced that Comedy Central's Stephen Colbert would replace David Letterman on the Late Show. Letterman, the host since 1992, announced during his April 3 taping that he would step away in 2015.

In the announcement, Colbert, who signed a five-year deal with CBS, praised Letterman and said, "I never dreamed that I would follow in his footsteps, though everyone in late night follows Dave's lead.

"I'm thrilled and grateful that CBS chose me. Now, if you'll excuse me, I have to go grind a gap in my front teeth."

In his own statement later in the day, Letterman said, "I'm very excited for him, and I'm flattered that CBS chose him. I also happen to know they wanted another guy with glasses."

It's a bold move and a great get for CBS, a bid to appeal to a wider and younger audience, and to attract the hip watercooler crowd that gets all its news from Jon Stewart and Colbert. It's also an implicit recognition that streaming viewers are more and more important to late-night shows.

The decision came uncommonly quickly, only a week after Letterman's.

So quickly, in fact, that many details were left hanging. Who is going to produce the show? Where will it be recorded? At the end of the year, Colbert, whose contract expires at that time, most likely will leave his celebrated Colbert Report . On Late Show, will he stay in character as the faux-conservative talk-show host who starts many of his sentences with "Nation -"? (Answer: Probably not.)

Contacted via Twitter, writer Emily Bazelon, a frequent guest on The Colbert Report, wrote that "I'm excited for him to remake network late-night. But for a small moment, I'm mourning the loss of his character. Such a distinct performance. And so much fun to grapple with!"

Colbert's name had been in the succession hopper along with those of other high-profile comedy hosts, including Ellen DeGeneres, who both spoof-auditioned for the gig on her own show and made clear she wasn't interested.

Brad Adgate, senior vice president at industry analyst Horizon Media, says he thinks "this succession was a premeditated move in the works for a while now. Colbert probably had the inside track. He was probably ready for an upgrade like this, having hosted his own show for most of 10 years. You know how the NFL drafts the best available? Well, it's like that. There aren't too many people who do this stuff, and he's one of them."

With 21 years on the Late Show and 11 years before that (1982-93) on NBC's Late Night With David Letterman, the namesake is the longest-running late-night host in U.S. television history. Colbert has hosted the Report since 2005. His hiring is a bid to widen the audience and skew it younger.

Letterman, who turns 67 on Saturday, attracts an audience about evenly split between the sexes. Letterman's audience has been about 2.7 million viewers nightly of late, and median viewer age has been around 56 for years now.

Colbert turns 50 in May, and his show attracts a 60 percent male audience. Colbert's audience hovers near two million with a median viewer age of 42.3. Stewart's and Colbert's shows often top the list of most-watched late-night shows in what's called the "key" 18-49 age group.

The move also acknowledges that many late-night viewers, young males especially, get their chuckles via streaming video rather than broadcast. The Stewart and Colbert websites are Nos. 1 and 2, respectively, among streaming late-night sites. They draw millions of viewers who tend to stay a while, which advertisers love.

Other late-night hosts such as Conan O'Brien, Jimmy Fallon, and Arsenio Hall are big leveragers of social media and website traffic, a knack older hosts Jay Leno and Letterman never acquired. CBS clearly is hoping Colbert's young staff and multimedia ways will attract and retain younger viewers.

With Barbara Walters, Leno, and Letterman all gone or going, it's turnover time for talk-show TV. A proliferation of late-night shows, from Chelsea Handler to Seth Myers, from O'Brien to Hall, have chopped up the audience. More competition comes from DVR time-shifting: Large numbers of viewers record prime-time shows and watch during later hours. So funnyman Colbert will be stepping into some serious waters.

215-854-4406 @jtimpane

David Hiltbrand contributed to this story.