Carl Friesen on his four tests on the usefulness of a 'review' article can be applied to pretty much all comment blog formats.

  1. is it relevant to the audience?
  2. do you know a lot about it? does your experience cover this topic?
  3. does your opinion have weight? are you qualified in this area?
  4. has this particular topic been 'reviewed' to death? In most niche aspects of knowledge businesses the answer is, fortunately, 'no'.

So if you are a qualified professional, discussing topics on your 'home turf' then really all you need to worry about is Number 1: Is it relevant?