So far, the consensus appears to be that blogs can be good sources of leads, quotes, or angles, but specific quotes or claims should be verified directly via conventional journalistic practice. I think that’s sound — and not just for quoting blogs, but for quoting anything or anyone.
Matt Ridings noted a concern I’ve heard from many journalists: “There is nothing stopping the blogger from editing the piece that you just used as a source, or in fact changing the viewpoint or context completely. This goes for online comments to that blog as well. …An op-ed piece in the newspaper will at least still be the same piece a month from now, regardless of whether the author has had a change of heart. Not so with a blog.”
Many news organizations routinely update online stories as new information comes to light. While updates are generally beneficial, they can potentially eliminate information which others might wish to quote.
Similarly, some organizations or government agencies will delete or revise problematic or controversialline statements or information after initial publication. Actually, I see revisions happening far more often on official corporate or government sites (often following media or blog coverage) than on blogs or news sites. This is one of many reasons why I always save a copy of anything I might want to quote or use in Furl.
The bottom line: Blogs are one of many source options, and no two blogs are completely alike. Each must be judged on its own merits — just like with any source of information. Credulously quoting a blog is no greater sin than credulously quoting a press release, unverified document, or reader tip. Keep your journalist hat on and you might find some blogs that can become trusted sources.