What is a blog? Why blog? Who should blog (journalists, marketers, CEOs, techies, educators, scientists, hobbyists)? Should blogging be pure or can you make money with a blog? Will blogging change everything?

Picture several hundred intense writer/thinker/bloggers at BlogCon in Cambridge, MA the weekend of Oct. 4 – 5, 2003 and you get the idea… a blogging conference is not for the faint-hearted. The metaphysics of blogging was a hot topic. The warmth of a virtual community enjoying face-to-face interaction was palpable.

As conference organizer (and veteran hackle-raiser) Dave Winer put it in his thank you message to attendees: “Did we figure out what weblogs are? Probably not – but we came closer.”

Well, I decided to take a crack at it. Here are my top 20 definitions of a blog. Take them with a grain of salt. Take them as a starting point to think about how you might use a blog as part of your Web site or communications strategy.

But don’t write Weblogs off as a passing fad, even if you’re not blogging yet yourself.

Blogging is…

#1 A form of unedited, authentic self-expression

#2 An instant publishing tool

#3 An online journal with freshly updated content

#4 Amateur journalism

#5 Something that will revolutionize the Web (think RSS feeds)

#6 A way to create community with your voters, er… readers (think 2,200 comments posted to the Dean for America blog in one day)

#7 An alternative to mainstream media (think InstaPundit by Glenn Reynolds and TalkingPointsMemo by Joshua Micah Marshall)

#8 A tool to teach students how to write (think Kaye Trammel at the University of Florida)

#9 A new way to communicate with customers (think Ray Ozzie, CEO of Groove Networks)

#10 A new form of knowledge management inside big companies

#11 A way for a bunch of navel-gazers to communicate with one another

#12 Something to keep you occupied when you’re unemployed (more people than care to admit fit into this category; have you noticed?)

#13 A way to think and write in short paragraphs instead of a long essay (which no one has time to read anyway)

#14 Your email to everyone, as A-list blogger Doc Searls puts it (i.e. a way to stay in touch with family and friends)

#15 A silly word that’s fun to say (“Gotta go blog now… “)

#16 A way of writing with a distinct voice and personality (think Halley Suitt)

#17 Something to talk about at cocktail parties (“I blogged Seth Godin and he blogged me back…”)

#18 A URL to add to your resume (as in TokyoTim, my 23-year-old son who’s living and working in Japan for a year)

#19 Something else to do with your mobile phone…think audio blogging and moblogging

#20 Something you don’t want your mother to read (what my mother says about blogging)