Blogging is actually a strange hobby. I myself have many interests and not nearly enough time to do only half of what I am interested in. So my blog suffers, often times there are months passing before I even send out a simple "I am still there - hang on". Which doesn`t get much attention anyways, but that`s not the point. I was always doing this for myself. I don`t need an audience.
I was near the point of tearing down my site, but until now I have always kept it alive and I have a place on the net to come back to. The good thing is: I never bothered to narrow my blog to any particular topic. (I had side blogs for special themes and they all died rather quickly.) So when I change my focus my site goes with me.
I think the basic point is: Do what you must. Try to do what you love as much as you can. Keep some fun alive. There is more than one way to do it.
