Do "blogs" or other social media postings violate public meetings laws?
A "blog" (Web log) is simply an individual's online journal. Facebook and other sites also allow individuals to post comments on a variety of topics. The site may invite comments and the user may or may not choose to post them. If posted comments, in response to a board member's original post, were to become a discussion among a quorum of the board members about district business over which the board has jurisdiction, that discussion could be viewed as a violation of the public meetings law. It certainly violates the intent of the public meetings law. Letters to a print or an online version of a newspaper could morph into a similar discussion.
Good board practice rules apply, whether it is an online site or a conversation at the football field. Be careful to follow all confidentiality requirements and district policies regarding the handling of complaints, don't make promises or speak for the board as a whole and don't say anything you wouldn't want printed on the front page of your local newspaper. A site that does not post reader's comments is more a lecture than a discussion and doesn't violate public meetings laws. Blogging, and other vehicles (e.g. Tumblr, Instagram), can be great ways to demonstrate transparency about the district's business. Inviting readers to "join the conversation" can build trust, and everything you accomplish requires trust.
I have seen online comments written by anonymous individuals and comments posted without identifying their authors. In such cases, the potential for harm through inaccuracies and rumors is high. A post containing information provided by a board member in a positive, open manner and the willingness to be accountable for accuracy will increase trust. The opposite, well, - it can do the opposite.