Yahoo! this month said it would include blogs on all its news searches, saying it would give readers more access to grassroots journalism.
Previously, search leader Google said it launched an engine tuned to scouring blog entries for fresh news and views.
While blogs have long been frowned upon by traditional media as amateurish, analysts say the public is increasingly looking to blogs for a different perspective.
Blogs, short for web logs, are also being boosted by other factors.
Traditional media such as The Washington Post newspaper are including blogs on their own websites. And mainstream journalism has received a black eye from recent incidents such as a plagiarism scandal and a CBS News television investigative report during the 2004 election campaign that ended up being discredited by blogs.
Yet blogs lost credibility, too, during the 2004 election when some reported premature exit poll results pointing to a victory by challenger John Kerry over President George Bush.
Michael Cornfield, a senior research consultant at the Pew Internet and American Life Project, said blogs are useful even if they may not be on a par with traditional journalism.
"Blogs are discussion forums, and I do not see any reason why they cannot be indexed" so internet users can search them, Cornfield said. "Discussion is an important part of the democratic process."
Google's search engine includes
blog entries in its results
Although Cornfield acknowledged a difference between blogs and mainstream news, he said the lines were being blurred.
"I have always regarded The New York Times as the paper of record and assumed what is in New York Times is true," he said. "But I don't trust them as much as I used to."
Julie Moos, managing editor at the Poynter Institute for Media Studies, said putting blogs and mainstream news in the same category, as Yahoo! has done, may be useful as long as blogs are clearly labelled.
"Different readers are able to discriminate among the types of content," she said.
"For some people, putting search results from blogs with search results from other news sources could be very helpful ... but other people may not distinguish the difference, and it might be more confusing."
Moos said blogs may not have the same journalistic norms as news organisations.
"In blogs outside of traditional news organisations, some have stated standards and some do not," she said.
"In blogs outside of traditional news organisations, some have stated standards and some do not"
Julie Moos, Poynter Institute for Media Studies managing editor
"I think labelling is the key, because people don't always know the source of information... Just like in a newspaper, we would label something as an editorial or analysis, it's helpful for someone to be able to find the same kinds of labels for blogs," Moos added.
A recent survey by Comscore Networks found nearly 50 million Americans, or about 30% of the total US internet population, visited blogs in the first quarter of 2005.
But another report by the web hosting company Hostway found only 28% believed blogs were as or more credible than newspaper articles.
Hostway Vice-President John Lee said the credibility of blogs is much higher among younger audiences who may be more cynical about traditional media.
"People under 30 found blogs to be just as credible as traditional media," Lee said.
The Hostway survey, however, found that 52% said bloggers should benefit from the same constitutional liberties and protections as professional journalists.
Pew analyst Cornfield said blogs and traditional news can co-exist even if they are different. Reading a blog "is more like being in a tavern than being in a newsroom", he said.
But he added: "Most bloggers would say we need the news organisations. It is symbiotic. News feeds on discussion and discussion feeds on news."