Having a blog from a dig is pretty good as far as I'm concerend .
Sure, but if a member of the public is, with limited (half day?) access, able to present, to the wider community, an overview better than those actually on and organising the dig it does make you wonder why we're paying the latter their wages. The Later Silbury blog states that, "Our aim is to post this blog once or twice a week... To keep your interest, we’ll all take turns to write about and photograph aspects of this fantastic opportunity, so follow us!"
Readers of the Later Silbury blog can make up their own minds as to whether that aim has actually been met.