What is a weblog?
Others have answered this question far better than I can.  Weblogs: a history and perspective is a particularly well done essay that gives a nice overview of the weblog phenomenon. 

What is this weblog?
This weblog is an informal list of links that I found interesting, maddening or compelling, usually accompanied by comments. I write about a lot of topics, some of which I know a lot about, and some of which I don't. Any personal website -- including mine -- is just a collection of ideas. I'm not held to the same standards as a reporter, I don't have fact checkers, and I don't have an editor. What you see on this page is just some of what I think about some things. When I read personal webpages myself, I give them the same weight I give the conversations I sometimes overhear in coffeeshops while drinking a latte. They're interesting, thought-provoking, and sometimes moving. But they aren't the final word. Before I decide what to believe about what I overhear or read, I do some research and reflection on my own. I encourage you to do the same and then decide: What do you think?"   

How this all started (for me)
The first weblog I ever read was Scott Kitchen's The Other Side, which I first found via  Where's George .  From there, I explored others and fell in love with the idea of maintaining one of my own. I started Breaching the Web the very next day (November 19, 1999), with some doubts about how long it would last.  I tend to be something of a dilettante -- I routinely pick up and drop new  hobbies, and even when I keep a hobby, I often fail to finish individual projects (I have three unfinished crocheted afghans in my closet, th oldest of which I started six years ago). Some might think this makes me flighty. I prefer to think it makes me interesting.

Where I came up with the name
The name of my weblog, Breaching the Web, is based on a type of experiment that is covered in almost every introductory Sociology class.  Breaching experiments involve disrupting the normal order of things and then carefully observing the results.  For example, you might try to haggle with the bus driver over the fare or eat with your fingers in a fancy restaurant and then carefully note the confused and angry  responses around you.  The idea is that the strength of the reaction is a measure of the broken norm's importance.  Strong reaction = strong norm.  Such experiments are called breaches because they break through the  surface of the social order and allow researchers to observe it from a new perspective -- just like a whale breaks through the surface of the ocean and suddenly sees things differently.

Why I do this now
More prosaically, I have come to see BtW as a way for me to practice non-technical writing.  I'm a good technical writer, but I've lost my skill at "normal writing."  I see this site as a way to practice writing everyday (or most days) in a relatively penalty-free environment.   Also, I'm an unregenerate progressive feminist with a whole passel of opinions that need sharing.  And on the internet, no one can interrupt you.