Since it began six years ago, the Internet radio service Pandora has changed the way millions of people listen to music online. Now the company wants to do the same for comedy.

Last week, Oakland-based Pandora added 10,000 clips by more than 700 comedians to its archive, and allows users to sort through them in the same way they do the site’s music: by picking a starting place — a comedian, type of comedy or even a specific joke — and then letting Pandora send a stream of similar material chosen by analyzing his or her taste.

“This is a logical step under the umbrella of personalized radio,” said Tim Westergren, the founder and chief strategy officer of Pandora Media, the company behind the service.

The comedy offerings stretch back to the days of Will Rogers and W.C. Fields, and include most of the greats, past and present: Bill Cosby, George Carlin, Bob Newhart, Jerry Seinfeld, Richard Pryor, Eddie Murphy, Joan Rivers, and Cheech & Chong. For more specialized tastes, there are routines by Triumph the Insult Comic Dog, Minnie Pearl and Yakov Smirnoff.

As with music, Pandora has developed a system to predict what its listeners will like. With the help of professional comedians, the company identified more than 100 traits common in jokes, from basic themes (ethnicity, family) and styles of delivery (dry, self-deprecating) to broader categorizations of how comedians toy with logic and language (spoonerisms, juxtaposition, misdirection).

Put together, these traits make a “genomic” composite of a joke or routine, and can be strung together to follow unexpected themes. For example, a listener who begins with Chris Rock may end up listening to Bill Hicks because of his similar “male perspectives, subject explorations, sarcastic delivery and slow delivery,” as the service explains.

For Pandora, comedy is one piece in a broad expansion that has made the company one of the biggest players in digital music. For most of its history it struggled to stay alive and raise money, but now, largely thanks to its popularity on smartphones, it has 82 million registered users and is preparing to raise $100 million in an initial public offering.

The company is still reporting losses, but they are getting smaller. According to Securities and Exchange Commission filings, Pandora Media lost $1.7 million for the year that ended Jan. 31, compared with $16.8 million the year before; advertising revenue, its main source of income, was $119.3 million in fiscal 2011, compared with $50.1 million in 2010.

Comedians and their record companies are hoping that Pandora will be a boon. Comedy videos may be hugely popular online, but aside from the occasional hit — like Dane Cook’s “Retaliation,” for example, which has sold 1.4 million copies, according to Nielsen SoundScan — most comedy albums have minuscule sales. The most popular current comedy album is Mike Birbiglia’s “Sleepwalk With Me Live,” whose 3,400 sales were not enough for it to make Billboard’s standard Top 200 album chart.

“One of our biggest challenges is that of discovery,” said Jack Vaughn, vice president of Birbiglia’s label, Comedy Central Records. “How do we get people who like a certain comic to find out about another comic they might like? This seems like the next phase of what the Internet can do for comedy.”

Each comedy track on Pandora is about three to six minutes, with some made up of multiple bits by the same artist. As with music, the comedy service is offered in a free version supported by advertising, and a paid, ad-free version. For its introduction, the free comedy streams will be supported by two Unilever brands with a penchant for comedic advertising: Klondike bars and Axe male grooming products.

Axe favors a bawdy, locker-room style of humor, said Rob Candelino, the brand’s marketing director. Since Pandora’s user registration includes demographic information like age and sex, Axe will show its 15-second ad spots only to men aged 18 to 24.

“We thought it was a sensational opportunity to reach our guy,” Candelino said.

Since it entered the market in 2005, Pandora has collected a mountain of data to help it parse what music people like and why.

But some of the people involved in the comedy service are just waiting to see exactly how Pandora’s comedic algorithms will work.

“It’ll be interesting when I find out who I’m paired up with,” said the comedian Adam Carolla, whose material will be included in the service. “I’m sure at some point someone will be insulted. There may be a lot of unintended comedy.”