I maintain an Involuntary Reboot Log — a series of posts about major system failures (kernel panics and hard resets) — as a means of measuring hardware and software reliability in a relatively objective fashion. By keeping a record of such failures and when they happened I'm able to make assessments of reliability trends (rather than make vague pronouncements like, "I don't think it's crashed in a while") and identify possible patterns and causes.
It's also a bit cathartic, writing in public about an unpleasant experience that caused you to lose time and possibly data as well.
Originally I used my weblog for the purposes of posting log entries, but later started using the wiki instead seeing as the entires weren't exactly newsworthy. Finally, once I added the snippets functionality to the site, I started use snippets for the involuntary reboot log.