Aslo worth a look is Unseen Academicals which deals with fans or the mentalityof a pack of supporters for a team brand.
Plus it might be worth checking out, The Folklore of Discworld by Jacqueline Simpson for additional information.
There are two other books which you should check out which may give you a futher insight: Terry Pratchett: Guilty of Literature and Guilty of Literature Second Edition, which is an expanded & revised edition of the previous 2001 edition, the latter was published in 2004 both are edited by Andrew M. Butler, Edward James and Farah Mendlesohn
So that should keep you busy for a while Shinpu.
He willnae tak' a drink! I think he's deid! , on the other hand though A Midgie in yir hand is worth twa up yir kilt.