Warner Brothers Records pulled out all the stops recently to promote a rock band, the Secret Machines, on the Internet. But there is one stop that might have been better left unpulled.

Earlier this month, Warner became the first major record label to ask MP3 blogs to play its music. The blogs -- which are relatively new but increasingly popular -- are personal Web sites that offer music criticism right next to the actual music, in the form of downloadable MP3 files.

But as is sometimes the case when marketers try to insinuate themselves into online communities, the company's approach did not go as planned. Warner -- which was part of the Time Warner media empire until February, when it was sold to a group of investors led by Edgar Bronfman Jr. -- ran into a culture clash with the small world of MP3 blogs, annoying some of the very people it wanted to win over, especially after one or more people at Warner apparently posted anonymous messages to make it appear that ordinary music fans were defending the label.

And because many MP3 blogs exist in a legal gray area -- to accompany their musings on the music, bloggers post complete song files, usually without permission -- the campaign put Warner in the position of currying favor with people whose views on file sharing are far more liberal than those of the music industry's lawyers.

Two weeks ago, at least eight MP3 bloggers received an e-mail message from Ian Cripps, a Warner employee. In the messages, which were identical and came with an MP3 file attached, Mr. Cripps told the bloggers that he loved their sites.

''We are very interested in blogs and I was wondering if you could post this mp3,'' he wrote. ''It's by one of our new bands -- The Secret Machines. They are an indie rock band and we would love for people to hear the band's music from your site. Here it is, listen to it and let me know if you will post it. Thanks!!''

The pitch to MP3 blogs was part of an ambitious online campaign that was the work of Robin Bechtel, vice president for new media at Warner Brothers and Reprise Records. The campaign's first unusual component was a decision to start selling the Secret Machines album through Apple's iTunes store and other online outlets last February, nearly four months before it was available on CD. The move drew attention to the album, which received strong reviews.

Ms. Bechtel said that the company had contacted many sites for the Web part of the publicity effort, and that the messages to MP3 blogs were an experiment. ''We're really progressive in trying things,'' she said.

The messages from Warner were big news among the bloggers. Independent labels like SpinArt have been paying attention to the MP3 blogs for months, sending them music as a way to get it heard in an age of tightly controlled radio playlists. Some bloggers saw the message from Warner as a sign that the major labels might spare their sites while cracking on illegal file sharing.

''We didn't know if there was a wink that came along with it that said, 'We don't have a problem with what you're doing,''' said Mark Willett, a contributor to Music for Robots (music.for-robots.com), a popular MP3 blog that attracts about 2,400 visitors a day.

Ms. Bechtel said the sites chosen by Warner ''were promoting music responsibly'' by offering authorized downloads or linking to online stores. She said that despite their small audiences, MP3 blogs were a good way to build positive word-of-mouth.

''Music blogs in general remind me of that friend you had in high school who would turn you on to the best bands,'' she said.

Many of the blogs were ambivalent about Warner's request: they were flattered by the attention but concerned about compromising their principles, or appearing to do so. In the end, Music for Robots was the only blog to post the track after receiving it from Warner (two others had already posted Secret Machines tracks independently). In an almost apologetic blog entry titled ''Music for Robots Sells Out,'' Mr. Willett wrote that the song was appearing there not because the band needed the exposure, but to establish a relationship with Warner and to let readers know what was going on.