LOS ANGELES - There was a time around 1997 when no matter where you were - in the car, on the StairMaster, at the dentist's office - you couldn't help but hear "My Heart Will Go On," the soaring Celine Dion ballad from "Titanic."

Resistance was futile. It did go on, and on, and on - an example not just of great marketing, but of the kind of movie theme song that no longer exists.

These extinct songs were big and poignant on their own, but also used skillfully within their films. They became "a souvenir" of the theatrical experience, as six-time Oscar-nominated songwriter Diane Warren puts it.

For decades, theme songs like "Evergreen" or "Arthur's Theme" or "(I've Had) The Time of My Life" were huge radio hits, often peaking at No. 1 on the pop chart and going on to win the Academy Award for best original song.

But in the past few years, filmmakers like Cameron Crowe and Wes Anderson (following the example set by directors like Martin Scorsese) have been more likely to choose pre-existing songs to punctuate a moment or create a certain mood. Then those soundtracks - like the ones for Crowe's "Vanilla Sky," Anderson's "Rushmore" or Zach Braff's "Garden State" - go on to be popular themselves.

So where did those original tunes go?

Jesse Harris, the Grammy-winning songwriter of Norah Jones' hit "Don't Know Why," who also wrote the music for Ethan Hawke's "The Hottest State," thinks filmmakers just don't bother to seek out them out anymore.

"What movies used to do," he said, is "create a nostalgia that was specific to the film itself, and the only way to do that is to use original music."

Of course, radio has changed vastly and become more genre-specific over the past decade, which hurts enormous movie songs with intended mass appeal, said Kid Kelly, a DJ on Sirius satellite radio's top-40 channel Hits 1. He points out that adult contemporary stations, where many of these movie themes traditionally have been popular, can be broken down even further to "hot," "urban" and "soft" subgroups.

"There's so much fragmentation out there, it's hard to find the right song," he said. "So my guess is that they just stopped looking."

There have been movies this year whose original songs have enjoyed some external success, if not become huge hits, including Eddie Vedder's "Hard Sun" from "Into the Wild" and the soundtrack to the indie musical "Once" by Glen Hansard and Marketa Irglova.

Kirsten Sheridan, daughter of veteran Irish filmmaker Jim Sheridan, who's directing her first studio film with the musical "August Rush," considered using songs from Hansard's band The Frames, but made "a really important decision" to go with original music. The movie, which opens Nov. 21, follows the elusive connection between the lead singer of a rock band (Jonathan Rhys Meyers), a classically trained cellist (Keri Russell) and their long-lost son (Freddie Highmore), who tries to reunite the family through song.

"We had three music supervisors hunting down three original songs for Jonny Rhys Meyers' band to perform and for Jonny to sing," Sheridan said. "I didn't want connotations, for people to have an idea in their heads, if they've heard them in other movies or had other preconceptions with pre-existing material. We felt it was really important for the film to feel real, for it to feel like a real band."

Besides, picking that perfect pop song isn't as easy as it might sound, says Crowe, who has created iconic music moments in such movies as "Say Anything …" and "Almost Famous." "You have to live and breathe it," he said. "You try to create that marriage and so often the record can overwhelm or be more eloquent than the movie."

Charles Bernstein, chairman of the executive committee of the academy's music branch - whose members vote for the best original song Oscar - points to 1969's "Easy Rider" as the turning point, with its soundtrack that famously included Steppenwolf's "Born to Be Wild" and The Band's "The Weight."

"That was the first time a soundtrack album became an entity in and of itself - a bunch of existing hits used to score an entire film," said Bernstein, who has composed scores for more than 100 movies. "Ever since then, there's been a split in the film community. There's `The Way We Were,' `Love Is a Many-Splendored Thing' tradition, then there's the `Easy Rider' tradition of getting a bunch of recognizable, youth-oriented songs from whatever era it is.

"What is really difficult, and why we give Oscars for it, is coming in and becoming a part of the filmmaking process - creating from zero, creating from a blank page, magic," he added. "Naturally, a lot of people are prone to take the easier road."