How far should blogging go in the work place?

I think you should limit your self about how much you blog about on an company blogging site. I think you should know not to tell any of the companies secrets online. I think that is just common since. But on the other hand I can see were most people go back to freedom of speach but in this case were you are giving out company secrets I really don't think that applies. I think it all goes back to the old addage think before you say or in this case type.