Many years ago, two of my friends had accounts at diaryland.com, so I decided to join the crowd and created one of my own. I liked the idea of being able to write about personal stuff and easily share it with a couple of close friends. The site had a pretty minimal social feature, but I fumbled my way into following a couple of strangers. The idea of being able to write stuff for "people" was intriguing, but I wanted to keep diaryland under wraps -- too personal for general consumption.
Then I stumbled upon livejournal. It had a better social element and random online friends of mine were already using it, so it was pretty easy to jump in. It was great because it gave me an outlet for whatever stuff I felt like sharing with my friends, plus the ability to interact with them. Eventually the platform started to feel stale, so I moved to blogger, and eventually to a self-hosted wordpress blog (this site), which I'm pretty happy with.