This is an edited version of a comment I posted on LinkedIn:
The question often comes up as to whether a company CEO should have a blog. At the very least, the CEO could, or should maintain an internal blog to communicate his or her vision and goals to staff. Ideally, the CEO should be the actual writer, but communications professionals could participate by helping the CEO to shape or polish blog content. By polish, I mean editing for length and clarity, and some proofreading.
The key is to ensure that the blog reflects the CEO's voice and communicates his or her beliefs and ideas as accurately as possible. If staff members don't recognize the CEO in the blog, they won't give the content much credence, and that can tarnish the CEO's integrity in their eyes, potentially leading to disengagement.
As for the CEO writing an external blog, it's only a good idea if it adheres to the principles above: that it be the actual thoughts and voice of the CEO. So the CEO must have the necessary time to write and maintain it. Again, communications professionals can help in determining topics to protect confidential company info, or by providing a bit of polish. But the content should, in the main, be generated by the CEO. It's an issue of integrity. If people discover that the blog is not being generated by the CEO, it can undermine their trust in your organization.
Time isn't the only issue as to whether a CEO should do an external blog. You have to think of that individual's temperament: how he or she will react to negative comments, for example. If there is a likelihood that the CEO will not stay on topic or maintain levelheadedness in responding to criticism, then the CEO may cause damage to his/her brand, and that of the organization.
So if you or your CEO is determined to do a blog, ensure the CEO is the writer of the content. Ensure the CEO keeps it updated. And ensure that the CEO is able to handle user commentary in an appropriate manner.