I wrote a couple of days ago about how I was using Day One as a Professional Journal. The developers liked the idea and added it to their page of Day One uses. Turns out there are a lot of clever and perhaps not traditional uses of Day One I hadn't considered. Makes me really wish there was a way to segregate Day One accounts so I could keep one for personal and one for work uses and try some of these.
Check them out: http://dayoneapp.com/guide/uses/