She has only a tiny record label behind her. Her music has almost never been played on commercial radio. And she isn't alive anymore to promote it.

Yet, somehow, in the four years since her death at age 33 from ovarian cancer, Eva Cassidy has managed to sell hundreds of thousands of albums in America and even more overseas.

While SoundScan figures put her American sales at 159,000 copies, her label chief, Bill Straw of Blix Street Records, claims the real tallies come close to twice that number. "SoundScan doesn't count mom-and-pop stores, which is where many of Eva's records have sold," he says. "And they just started counting a few months ago, where her record has been No.1."

In fact, Cassidy owes much of her posthumous success to the Internet. Three years ago, Blix Street began spreading word on Cassidy through chat rooms and Web sites. "When you're selling a record slowly, with no major media behind it, you can't get stocked in stores," Straw says. "So when people hear about her, they go to the Web, where they're used to finding obscure records."

A major segment on National Public Radio several months back also spread the word about this singer, who never gave a concert outside her hometown of Washington, D.C. That story helped inspire the makers of two TV shows, "Dawson's Creek" and "Judging Amy," to feature bits of Cassidy's version of Sting's "Fields of Gold" as background music.

It's not surprising that even a quick snippet of Cassidy's music could inspire interest. Blessed with a warm contralto and a gift for fine phrasing, Cassidy's singing has the dignity of Roberta Flack, the elegance of James Taylor and the mournfulness of Sandy Denny.

Cassidy's music treats cabaret and gospel music with the tastefulness of folk-rock. "She's emotional without being saccharine," Straw explains. "Her music was understated. While singers like Mariah Carey and Whitney Houston have great instruments, they're forced into histrionics to sell records. There's a false drama that Eva avoided."

The modest singer got her break in the early '90s through her guest appearances with D.C. legend Chuck Brown. There, she developed a cult following that led her to the attention of Straw's company. By the time he signed her in '96, she was sick. "I signed her in October; she died the next month," Straw says.

It was only after her death that her parents got to hear the range of music she recorded. To spread the word, they made all her recordings available to Blix Street. So far, three albums have been fashioned from the tapes Cassidy left behind. The best, "Songbird," features the title cover of Christine McVie's song, plus a version of "Over the Rainbow." A video has been cobbled together for the latter, which in England just helped "Songbird" go platinum.

Straw has no doubt that the tragedy of Cassidy's story has drawn people. "But people die every day," he says. "This wouldn't mean so much if the music weren't so strong."