I recently ran across Richard Bejtlich's post on Why blog? and I asked myself that question. I currently run three different blogs focused on different things and found that while there are some similar reasons for all three, there are some different reasons.
Primarily I agree with Richard's first reason Blogging organizes thoughts. I find the process of collecting and expressing my thoughts enjoyable. My job requires me to do this constantly, but usually under time pressure, so it's nice to have an opportunity to do this at my pace.
Another reason I do it is because I have a desire to share what I've learned. It drives me nuts to think that I've just spent an hour figuring something out that someone else already had or that someone else may be fated to repeat my efforts. This is a big motivation for my Ubuntu experiences blog. It is a diary of my system administration experiences on my home network. I started it for my own benefit so that I could later remember what the heck I did and decided to put it online so that others could hopefully benefit. Based on the amount of traffic and comments it gets, I'm happy with how it is going.
Security Unwrapped is my attempt to atone for my profession's failure to really make computer security understandable usable. My goal is to make computer security understandable for my mother (hi mom!) It consists of my pointing our stories and articles I think achieve that as well as my own writings to try to take aspects of computer security and explain them in simple terms. This writing is by far the most work of the three blogs, I wish I could do more of this, but it takes time and inspiration.
The third (and final for the moment) blog is blog.vwelch.com. Honestly, I started this because I had stuff I wanted to blog about (like this) that is out of scope of my other two blogs, so I intentionally scoped it as a catch-all. Tying it back to Richard's post, it's probably most accurately described by Blogging captures and shares thoughts.
Well, that's that. Thanks for listening. Happy blogging.