One of the leading figures in Web radio is coming here to listen to his listeners.

Pandora founder and chief strategy officer Tim Westergren will be in town tomorrow to talk to Pandora listeners about the service. The meet-up will be held at the SouthSide Works Cinema at 7 p.m. Admission is free, and the event is open to anyone who wants to learn more about Pandora.

While Internet radio stations cater to a wide range of both mainstream and niche musical tastes. Pandora takes that one step further by serving as a music recommendation service that tailors individual streams of music to each listener. For example, type in "Beatles," and you will hear a Beatles song, followed by other bands -- Rolling Stones, Queen, The Who and music with a similar musical qualities. Or request a favorite song, and Pandora will introduce the listener to other songs with a similar sound or mood.

People who prefer to hear music by format can choose from an array of genres and subgenres. Rock, for example, is broken down into adult contemporary, punk and post punk, British invasion, doo-wop, grunge, indie, metal and others. Classical listeners can hone their selections to baroque, romantic, symphonic, choral and more.

The goal: to give listeners exactly what they want to hear and introduce them to new music and artists they might like based on individual musical tastes.

Westergren has been one of the most vocal Webcasters leading the charge in the ongoing battle to reduce per-song-played copyright fees Webcasters are now required to pay to record labels. The increased fees for streaming music online were set by the Copyright Royalty Board last year.

Commercial radio only pays royalties to composers and not to artists or record companies.

"It established a fee structure that's disconnected from the economic realities of Web radio, and a fee that's dramatically higher than any form of radio play," Westergren says. "It's unrealistic, even with a very efficient, fully mature business monetizing at levels close to broadcast radio, which doesn't pay any performance fees at all. Left unfixed, it would kill Web radio, which is not in anybody's interest."

Westergren has said that Pandora would be forced to shut down its popular service if the CRB rates were not lowered. Earlier this month, however, the House and Senate passed the Webcaster Settlement Act of 2008, which allows Webcasters and SoundExchange, the organization representing the record labels, to negotiate a royalty fee. Westergren is encouraged by the move. "It seems to be getting close to a solution. For the first time, I'm kind of optimistic that we can negotiate a solution."

Westergren started out as a musician after graduating from Stanford University, where he studied computer acoustics and recording technology. He spent the first part of his career in the music industry, playing in bands, composing and producing. But he wanted to find a way to build a new kind of bridge between emerging talent and potential audiences.

"I wanted to figure out a way to help musicians more easily find their audience. Having been a working musician, I've always been interested in that challenge."

Westergren launched Pandora in 2000. Since then, its has grown into one of the most popular online music services, with 17 million members. An estimated 30,000 of them are in the Pittsburgh area, according to Westergren.

The Pandora experience has gone wireless, too. It's available on mobile phones, including the iPhone, and through several home Internet radio receivers, which enable people to listen to Internet stations without turning on a computer, by making the connection through a wireless router and broadband service.

"That's a big initiative for us, trying to make Pandora available anytime, anywhere." Other priorities include continuing to expand its music database and to make the service available to international listeners -- currently Pandora is only licensed to provide music to U.S. listeners.

Although Pandora is a high-tech company, the matching of the music played is not a mechanical process; it's all done manually. The company employs a team of around 50 musicians.

"They listen to the songs one at a time and analyze them among 400 musical attributes," Westergren says. "They manually measure every little detail" in terms of melody, harmony, rhythm, instrumentation, vocals and lyrics. "That's the kind of connective tissue that pulls songs together. We use that information to link songs."

It's a time-consuming process, and the company is constantly adding songs to its database, Analyzing a simple pop song can take 15 minutes, while a longer, more complex composition, like a symphony, can take around two hours.

Meet-ups like the one here tomorrow are an ongoing process for Pandora, and they have taken place in more than 100 cities so far. One common thread he has found is listeners' enthusiasm for the way Pandora delivers music.

"I'm struck by how much people care about it, how this passion for music is behind their interest, how strong it is, how universal it is."