There is a lot of other good stuff on the site, notably a tribute to Drif, who produced printed guides to bookshops back in the 1980s. It quotes some of the acronyms he used in his entries:
I also recall AWYW (Asks what you want), but it is not included in the list on the site.
ETGOW - Easy to get on with;
FARTS - Follows you around recommending the stock;
NETGOW - Not easy to get on with;
WAD - Worth a detour;
WAP - Worth a pilgrimage.