CBS (NYSE:CBS) and Time Warner (NYSE:TWX)/Warner Bros.' The Big Bang Theory just got a big renewal for three more seasons, extending the hit comedy through the tenth season. It's the second time that the series has received a three-year renewal, and will be creator Chuck Lorre's second sitcom to cross the 10-season mark after Two and a Half Men, which is currently in its 11th season on CBS.

Ratings for The Big Bang Theory have improved substantially over the past seven seasons, and it is currently the number one rated comedy among 18-49 year olds. An average of 8.3 million viewers tuned in during the first season, and that number rose every season until its audience reached 18.7 million viewers in the sixth season.


Source: CBS

That's a stark contrast to Two and a Half Men, which started out strong with 15.3 million viewers in the first season and has held steady between 12.7 million to 16.5 million viewers ever since.

Big ratings equal big salaries
The main actors in the show are reportedly negotiating major salary increases with Warner Bros., according to a recent report in The Hollywood Reporter. Jim Parsons (Sheldon), Johnny Galecki (Leonard), and Kaley Cuoco (Penny) are expected to negotiate together to seek up to $1 million per episode, a huge raise from their current pay of $325,000 per half hour. Simon Helberg (Howard) and Kunal Nayyar (Raj) are expected to negotiate their terms together.

If Parsons, Galecki, and Cuoco manage to secure $1 million per episode paychecks, it would nearly match the $1 million ($1.27 million after inflation) that the cast of Comcast (NASDAQ:CMCSA)/NBC's Friends received in 2002 for the hit comedy's final season, its tenth. It would also match Ashton Kutcher's $1 million per episode paycheck for Two and a Half Men, although it'd be a far cry from Charlie Sheen's deal for nearly $2 million per episode before his character was unceremoniously killed off in the ninth season.

Good sitcoms are hard to find
In the 1980s and 1990s, half-hour sitcoms were a dime a dozen. They were cheap to make and attracted plenty of primetime viewers, which translated to an abundance of ad revenue.

In the late 1990s, however, audience tastes started to shift from family-friendly fare to adult-oriented sitcoms such as Seinfeld and Friends. Single-camera comedies such as The Office, Modern Family, and Parks to Recreation subsequently ditched the trademark live audiences and focused on mumblecore humor instead.

Yet despite this evolution (or devolution) of the genre, major networks such as Disney's (NYSE:DIS) ABC, CBS, Fox (NASDAQ:FOX), and Comcast's NBC continued trying to recapture the magic from The Cosby Show, Friends, and Seinfeld with a new generation of sitcoms.

Unfortunately, many of these sitcoms lacked any of the charm of those older shows. Shows like CBS' 2 Broke Girls and Fox's Dads mistakenly assumed that bland writing and offensive jokes could replace well-timed humor. Other shows, like Fox's New Girl, turn every character into a fool, without realizing that good comedy also needs straight characters to serve as comic foils.

Why The Big Bang Theory is such a hit
That's why The Big Bang Theory is such a rare gem in the sitcom world -- it's a show that has a seamless ensemble cast, much like Friends, and still knows how to set up charming comedic situations without resorting to shocking or offensive jokes. And unlike Two and a Half Men -- which keeps chugging along on empty despite the widely publicized meltdowns of stars Charlie Sheen and Angus T. Jones -- The Big Bang Theory still seems to have a lot of fuel left in the tank.


Source: CBS

In addition to solid situation-based writing, the show's recurring themes of sci-fi, comic books, video games, and "geek culture" make the characters much more relatable than characters on other sitcoms. That's a key strength that it shares with Cheers, Seinfeld, and Friends -- and one that many sitcom writers repeatedly fail to grasp.

What The Big Bang Theory means to CBS
CBS is very keen to keep The Big Bang Theory on the air for as long as possible, since it is currently the most expensive non-NFL show to advertise on, according to a recent report from Adweek:




Cost per 30 seconds of advertising



Sunday Night Football




The Big Bang Theory




The Voice




Modern Family




The Simpsons


Source: Adweek.

Powered by hits like The Big Bang Theory, CBS' advertising revenue rose 4% year over year to $8.8 billion in 2013, accounting for 58% of CBS' total revenue.

My final take
The Big Bang Theory isn't the only show that CBS renewed. The network, which is currently tied with NBC as the most watched network among adults ages 18 to 49, also renewed 17 other shows, including hard-hitting heavyweights like NCIS, Person of Interest, Criminal Minds, and Elementary.

With such a strong slate of popular shows, CBS will easily maintain its leading position in network TV for the foreseeable future, and its stock -- which is already up more than 40% over the past 12 months -- could keep rallying as a result.

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Leo Sun owns shares of Walt Disney. The Motley Fool recommends Walt Disney. The Motley Fool owns shares of Walt Disney. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.