I moved from Toronto, Ontario to London, Ontario in May of 2005. While this journal had been used to keep track of my life in general, it had fallen off in use before I moved (due to lack of Internet), and saw a surge of use afterwards, as a way of keeping in touch.
As of August 2010, I've started using Live Journal more often again, as I had found that social networking tools do a poor job of recording history: Those entries are of the moment, and the tools make it hard to reference the past, while blogging can be around for a long time to come.
I primarily write so that I have a record of my history, of things that I've done. I've recently begun using LiveJournal with a focus on longer updates, gaming summaries, or for building up my thoughts and ideas.