[xtc]

I think the primary point is that the successful founders we can think of don't blog regularly. I could think of a few exceptions to this that have been mentioned in other comments (Freedman, Musk, Spolsky, etc). However of the exceptions even fewer blog on a regular basis.

There will always be exceptions to this and I hope people don't read remarks like Keith's as how-to guides. It's only a pattern that fits the mold. Don't think that your time is always too precious to 'share insights & experiences' as Hunter stated. That should have its time and place as well. It's very helpful to outsiders such as myself.