Thinking in public is a difficult habit to get into, though, because public is the place where we're supposed to not screw up, and thinking on the fly inevitably involves screwing up. Blogging with any regularity in essence means committing oneself to making one's intellectual fallibility visible to the world and to the unforgiving memory of the Google cache. This is particularly a problem for academics, who are, after all, professional thinkers; we have a culture of making it look easy, and of concealing as much as possible "the raw material of poetry in all its rawness."
It's always hard to give voice to things that you aren't totally confident in. But I think this is also a matter of tone. If you write like someone seeking, as opposed to someone declaring, most fair-minded people respond in kind. If the table is set for scientific inquiry, that's what you'll get. If it's set for Crossfire, you'll get that too.
There's also the matter of having your thoughts publicly discredited. But the fact of the matter is that professional thinkers are discredited all the time. They survive, and sometimes even thrive. But with the internet, you can be discredited by an amateur thinker (I mean amateur in the most direct sense.) Indeed, it one of the lessons, for me, of blogging is that that intelligence is not the property of universities, fancy magazines and literary journals.
I think this is good too. You don't want to end up like this.