WASHINGTON — When Nokia Corp. released its camera smartphone last fall, the marketing campaign cut back on news releases and flashy ads. Instead, the company sent sample products to 50 tech-savvy amateur bloggers with a passion for mobile phones.

The tactic paid off, as word spread online about the N-series phone, driving up sales and contributing to a 43 percent profit boost for Nokia last quarter.

"So many blogs picked it up that it blew out our server twice," said Andy Abramson of Comunicano Inc., who developed the blogging program for Nokia. "We were getting thousands of hits per second. When you look at the body of information that was generated around this, we knew we had something very special."

Companies are increasingly partnering with hobby bloggers to harness the burgeoning influence of online buzz. Through the digital grapevine, companies reap the marketing rewards of free publicity, higher rankings on search engines and immediate access to conversations with consumers.

Blogger relations experts have joined public relations and advertising teams. Movie studios are giving bloggers sneak peeks at deleted scenes and Hollywood gossip to promote movies and DVD releases. Startup technology companies in Silicon Valley are hiring public-relations firms to grab mentions on the hottest tech blogs. Even pet-care companies and publishers of religious books are trying to get nods on blogs, even if they have only a few readers.

The more bloggers exchange links and ideas about a company, the better chance it has of appearing on a search engine — an appealing draw as companies clamor for more visibility to consumers.

Collaborating with bloggers, especially those who maintain lesser-known blogs, is the fastest way to put niche-specific content in front of people who care about it most, said John Cass, director of blogging strategies for the Internet consulting firm Backbone Media Inc.

"In blogging, the culture is all about reciprocal discussion," he said. "A couple of years ago, it was hard to send a message to a webmaster and ask them to link to you. Now, if you can get mentioned on a few obscure blogs and get taken seriously, 20 to 40 links can make a huge difference for your business."

Alan Smith, 30, started writing a wine blog, Winesmith (www .winesmith.blogspot.com), in May as a way to learn more about the industry. In the past month, four budget wine distributors have asked the Washington resident to review bottles of wine or direct readers to online wine stores.

"They're trying to target this emerging market of budget wine drinkers," Smith said. "It's an effort to partner with bloggers to seek out newer and broader markets instead of being in this rut of looking at just traditional wine media." That approach, he said, "doesn't really speak to me."

Smith said he didn't mind reviewing an occasional free bottle of wine if it helped expand his readership. But some bloggers think that accepting such offers undermines their credibility.

Alex Giron, 26, a Web developer in Arlington, Va., started his blog, CSS Beauty (www.css beauty.com), two years ago to archive his favorite Web sites. Now he gets 8,000 daily visitors and at least three pitches a month from companies seeking a mention on his site or trying to persuade him to sign up with hosting software. He always turns them down.

"To me it feels like selling out, because I do this for fun," he said. "They're totally targeting sites like this. That's why I keep getting offers and offers — they never stop."

Marketing firms are advising companies to have conversations with bloggers rather than simply pitching a product and giving free samples. Follow the blogs carefully and join the dialogue by responding to posts only when it's appropriate, suggested Fionnuala Downhill, chief executive of Elixir Systems, an Arizona-based agency specializing in increasing companies' search rankings.

Inserting unrelated comments just to score a link will only offend bloggers, she said.

For example, Kim Bloomer, who writes the blog Aspenbloom Pet Care (Aspenbloompetcare .com), gets angry when pet-care companies post links just to sell their products. Her response is to delete their posts.

"As soon as you try to control the message, it takes away from the whole spirit of blogging," Downhill said. "Once a commercial site influences a blog, a lot of people really frown on that. It's supposed to be consumer-generated, not company-generated."

To keep its efforts from being construed as manipulative, Los Angeles marketing firm M80 tries to provide bloggers with content they naturally gravitate toward. When Fox released the first season of "Family Guy" on DVD, M80 generated buzz by sending bloggers funny clips of the show's cast rehearsing. It circulated on the Internet so fast that the company now supplies bloggers with exclusive content each time a season is released.