Although I may be an extreme case, I use Dokuwiki for notes/journals/logs. I wanted something that was OSS, as I am somewhat uncomfortable providing brain dumps to a corporate entity in exchange for a license. Wiki markup is great for quick keyboard formatting, and all data is saved in flat files, so a rsync via cron takes care of redundancy/backups. Revision control works, and I can quickly create a new user with limited access if I need to share, or export to PDF.