Radio is a constantly changing business, especially now that it's faced with new competition in the form of personal media players, satellite radio and Internet broadcasting. Here's a look back at some of the significant local and national events that shaped -- and shook -- the medium in 2007.

One of the shortest-lived formats in local radio history launched this year: The Zone, a male-oriented talk station on the former WTZN-FM (93.7). It lasted six months.

With a solid lineup of local talent that included Scott Paulsen, John McIntire and John Steigerwald, plus syndicated Dennis Miller, it offered listeners a fresh approach to talk. It wasn't exclusively political, but instead ran all over the pop culture and sports map.

Some listeners found it entertaining, others found it offensive. The real problem was that not many listeners found it at all. It failed to catch fire in the ratings, and the plug was pulled abruptly in October.

It wasn't a banner year for intelligent and unique local talk hosts. The year ended with the loss of Doug Hoerth, whose contract wasn't renewed at talk station WPTT-AM. Hoerth, a 28-year veteran of the Pittsburgh market, is a different breed of talk host than today's axe-grinding norm, instead keeping the focus on pop culture, movies, entertainment and himself. He is a unique talent who clearly knows and loves radio.

Paulsen's all-too-short comeback on the former WTZN proved that the longtime former WDVE morning host could do an entertaining, witty, locally focused program that really connected with listeners and callers.

McIntire and producer sidekick Gab Bonesso brought some laughs to the work day afternoon slump. While many listeners preferred the McIntire of his TV "NightTalk" days, it was still something different.

Radio formats go away all the time, but they hardly ever come back. With the demise of The Zone, a perennial local favorite -- B94 -- was reincarnated.

The switch was bad news for talk radio, but good news for music radio. The popular contemporary hits format previously aired on 93.7 before the station picked up Howard Stern and switched to a rock format in 2004. It's back with a refreshed playlist for a new generation and new call letters -- WBZW-FM. On-air teasers indicated that former B94 morning personality Bubba will return to the station in 2008.

Commercial radio -- especially talk radio -- thrives on controversy, while public radio usually doesn't. But jazz/NPR station WDUQ-FM found itself in the middle of a firestorm when it turned down $5,300 in underwriting messages from Planned Parenthood. The reason: Duquesne University, which holds WDUQ's license and houses the station, felt that Planned Parenthood's message ran counter to Duquesne's Catholic mission.

The decision raised hackles among some listeners, who believe the station should be able to operate independently.

Syndicated Don Imus made an incredibly dumb, insensitive and racist remark about the Rutgers women's basketball team and lost his job over it. Many thought his career was over, but he's back on the air at WABC-AM in New York, proving that while there are consequences for serious mistakes, sometimes they aren't serious consequences.

But it did spark a national dialogue about what's not appropriate to say on the air, even in the standard-less world of shock radio. There's still a line, although many personalities admit they don't know where it is. The fact that it's always moving clouds the issue even more. At least the Imus flap proved that the line still exists.

In another on-air ideological battle, syndicated Michael Savage (who's heard here on talk station WPGB-FM), lost several sponsors after delivering an anti-Islamic tirade on this show. The Council on American-Islamic Relations (CAIR), an organization whose mission is to correct misrepresentations about Islam, posted audio on its Web site of Savage's rant, and called for an advertiser boycott. Savage in turn sued CAIR for using the clips and taking his remarks out of context.

The controversy over Savage launched the formation of a new watchdog group -- The Hate Hurts America Community and Interfaith Coalition, which was formed to challenge hate speech on the radio.

The big news in satellite radio is that its sole two players, once bitter rivals, now want to get married.

XM Satellite Radio and Sirius Satellite Radio announced plans to merge the two services in February. The companies argue that by combining into one larger satellite broadcaster, they could offer more diverse programming, eliminate duplication and maybe turn a profit.

The new company promises a better deal for listeners, including a la carte packages starting at $6.95 a month for their choice of 50 channels -- compared to the current $12.95 monthly subscription.

Shareholders approved the deal, but the Justice Department and the Federal Communications Commission still have to give it the green light.

It was a rough year for Internet radio broadcasters. The Copyright Royalty Board established higher royalty payments, which Webcasters say will eat into revenues and make it impossible for many in the fledgling industry to continue broadcasting on the Web.

Royalty rates for satellite radio and cable TV music providers have been set, and appeals to establish a more equitable deal for Webcasters will start next year.

Mainstream broadcasters are gearing up for their own version of the same battle. The musicFIRST (Fairness in Radio Starting Today) Coalition, a group of artists and recording labels, is lobbying to make radio stations pay royalties to the performers on the records they play. The Performance Rights Bill has been introduced in both the House and Senate. Broadcasters are fighting back with their own bill -- the Local Radio Freedom Act. The fight gets underway in Congress next year.

Arbitron introduced new technology for measuring audiences -- the Portable People Meter (PPM).

The electronic device tracks listening habits and promises to be more accurate than the present written diary methods, which depends on people's memories and willingness to be accurate in cataloging what stations they listen to.

In Philadelphia and Houston, the first two markets to make the switch, a significant change in results is already evident, and industry observers say that the new ratings may reshape the current rankings.

Arbitron is gradually rolling out the new technology out in selected markets. Pittsburgh is scheduled for 2009.