Book Festivals

I sat in on a meeting the other day geared to set up a new literary festival. It is starting from the principle that such festivals are a good thing. In local terms that may well be so. In national / international terms I'm more interested in the question 'What niche has yet to be filled? What's unique to this area that has not been reflected elsewhere? What greater purpose might a festival serve?'
My thoughts were strengthened by a conversation with a publicist the other day. She pronounced herself utterly weary of one of the big festivals, in Oxford. Though backed by The Times, it seemed to spread itself too thinly. She had taken along one of her big-name authors to find herself in a room seating 30-40 max, and they sold 3 or 4 books, all a touch demoralizing.
My upcoming appearance at Edinburgh will beonly my second such - the earlier one was at the cheery festival in Wigtown (which certainly has a purpose as a foundation stone for the whole community, reinventing Wigtown as 'Scottish Books town', their own version of Hay on Wye).
I'm intrigued by London's new venture, London Lit festival. Spinning off from the web, it has a fine grassroots feel to it. This isn't someone imposing a festival on a populous, it's the writers and booklovers in a city coming up with their own events, presenting their own festival programme. I look forward to seeing how it tiurns out.