Yup - I'm sure you're right that it happens all over the place.  And were it purely a civil matter it would not be worth pursuing, except perhaps as a service to bloggers in general who might feel their words in future coming back to haunt them in a similar way.  But if there's any chance of it being an election offense I think it's worth checking because it was clearly done maliciously (despite there being no previous animosity between me and the Labour candidate, now councillor).