What is a weblog? A personal web page, or online journal, updated easily by an author, that links outward to other material on the Web, and presents original content--typically, links and commentary--in a rolling, day-by-day fashion, with the latest entries on top.

But also:

* Some weblogs have comment sections after every item, so in a sense every item is an item submitted for public comment.
* Some weblogs have a long list of other blogs they name, highlight and link to, (a blogroll, in the vernacular). This an author uses to define a conversational field, as if to say: "listen to me as I talk to them."
* Weblogs don't have to be, but they often are designed with a given look and feel, which is to say they define a particular kind of place. To Joi Ito, a weblog is primarily that, a place its users enjoy. He says that reading his weblog is something like visiting his house. If so, it's a talking house.
* Jeff Jarvis, author of Buzzmachine, a popular and newsy weblog, says: "know my blog, know me." According to Dave Winer, one of the pioneers of the form, a weblog is the "voice of a person."

All weblogs offer text, increasingly they have photographs, some include audio, some now present video (and some have ads.) The weblog incorporates these earlier media forms, turning them into tools of expression almost anyone can learn to use. The software behind the form allows for production values high enough that individual authors on the Web suffer no immediate disadvantage in comparison to very large commercial providers. There's something extremely democratic about that.

Remember the rationale for public access television? It was supposed to give individual television makers a place on the cable dial. Weblogs are a more effective public access point. Because they are "live" on the Web, and the Web is World Wide, the millions of weblogs already out there have some ability to compete in the same public space as hugely capitalized media companies.

Although it is still a tiny universe, and not a real threat to the established media or the professionals who operate it, the sphere of weblogs is capable of something bigger inventions have not achieved. As Jarvis says, the weblog gives people in the audience a printing press, and thus access to their own audience. There's something extremely democratic about that, too.

And even though we know that only a small, unrepresentative fraction of a percent will start that press up, the fact that it can be done has a radiating effect. Andrew Sullivan got more readers for himself, through his weblog, than he ever had as editor and columnist of the New Republic magazine. Granted that he began with every advantage as a journalist and writer with a track record in public controversy; still, with andrewsullivan.com he showed that an individual provider could compete with long-established journals of opinion. "If the goal of opinion journalism is not ultimately money but influence and readers," Sullivan wrote, "the blogs are already breathing down the old media's neck."