In Ray Ozzie's blog Jon Udell , answers a question by Ray Ozzie about the difficulty of partitioning intermal vs external information when having a public and private company weblog.
It's a very interesting read
To the extent that thoughts sharable within your company happen also to be sharable outside of it, I've always believed it makes sense to make those thoughts public
There is, to be sure, a cost involved in thinking about which messages go where (and why). It's my belief that fluid negotiation of the boundaries between public and private space, and appropriate use of scoped zones of collaboration, are increasingly necessary communication skills.