The PC is in our bedroom, so I have to wait until my girlfriend first. I'm up with the kids anytime after 5am - usually around 6am though - and then am able to get online around 7:45. After that I try to keep on intermittently throughout the day.
It's become a form of social outlet - which is great while my children are still very young and very demanding.
More than that, though, is that I'm creating a network of backlinks to my sites, to help them rise up in search engine rankings. Any excuse, really.
