Writing a blog entry on an iPad is rather painful, but possible. I wouldn’t want to write more than a few lines this way, but it’s nice to have in a pinch.
Editing is possible using gestures to zoom. Still, it’s tedious. There seems to be some predictive text input, but I type faster than it prompts–even one-fingered.
So far, I see the iPad as a great consumption device. I don’t yet see it replacing a notebook for creating content.