What do I mean by posting Just Say "No" To Blogs? on a blog. Has 'the simple teacher' guy lost the plot? Probably, but that post is for another day.
As we manage the dynamics of a Web 2.0-based classroom, the integration of the tools available to us must not overshadow the development of the learner. If a blog will enhance the learning process, then blog. If not, then choose a different tool or, better yet, let the students choose the tool. Remember "You do not need to bring in an elephant to teach the color grey." (Liz Dunham, c.1990)
We must also make the permanence of the Internet very clear to users. Once comments, pictures and videos are posted, they are in cyberspace for anyone and everyone to see. Check out the Once Posted You Lose Itvideo which brings home the point of permanence.
As with any tool, its effectiveness is determined by the users. Choose your tools wisely, provide a structure for safe usage, and support authentic learning.