I toyed with the idea of doing something like this ages ago, but decided against it.  I felt it would become something akin to signing things, and it's open to the equivalent of forgery.
What's to stop someone from creating content you don't agree with, and then putting your tag on it?<p>To partially offset that you could create a page under your control that has a link to every page with a verified personal tag.  Use Google alerts to send you the links automatically, and anything you don't recognise, check it out.  Have an "I refute ..." or "Name and Shame" section to highlight those occurences that are not legitimate.