If by "journalism" you mean "the objective reporting of news and events," then no. Most Webloggers aren't objective, and have neither the resources nor the experience to report news.
Weblogs tend to be more visceral and more emotional. They give you the impressions, experiences, and opinions of the people writing them. On newsworthy topics such as war or terrorism, these impressions are often inaccurate and colored by emotion.
Weblogs have a great deal of value, but the value isn't journalistic. Weblogs aren't journalism so much as a playground of ideas. Ideas propogate very, very quickly through the blogging community; as such, the community is an excellent touchstone of the impressions left by an event.
It's best to think of weblogs as a way to gauge the quick, emotional reaction of a society to an event, rather than thinking of weblogs as a way to get in-depth, detailed information about an event. Both weblogs and traditional media can fill both roles, to greater or lesser degrees, but each has a different focus, and neither is really likely to displace the other.
And the amount of misinformation and ignorance in the blogging community can, at times, be downright terrifying.