Nononono . . . that would be like the landlord paying a visit!
Welcome to the site, Geoff.
I could be wrong about this, but I'm sure I read somewhere that Terry stopped visiting alt.fan.pratchett because too many of the people there used to slag off his writing. And he found that if people were telling him ideas for books, he would have to immediately discount any plot that came anywhere close in case people said that he'd stolen their idea. Unlikely as it may seem, this sort of thing really happens.
Thanks for the 'welcomes'.... yes, he had to stop visiting eventually because of those reasons and also to get away from the constant string of AOL'er (when aol finally - unfortunately - got a link in to the newsgroups) who always
started off with "You're not the real
Terry Practchett are you?" (Except it would be phrased "ur nt the rl trry pratchet RU")... generally they were the ones to whom the name 'Merkin' first became attached.
PTerry did not suddenly turn around and say "I'm not taking part any more." but rather withdrew gradually until one day someone remarked that we'd not heard anything from him for a while - at that time someone, my memory fails a bit but I think it might have been Steve Briggs, announced that he'd cut ties.
Tip: Never put out a bonfire with your face.