There's more to this than just a straightforward clash of views. In Mailer's heyday, text was sacrosanct. It had been commissioned, sweated over, polished, edited, printed and marketed. There were enough barriers between aspiring authors and "real" writers to ensure that everything published was endowed with some kind of kudos. It's no surprise that Mailer (right) once said that "the Internet is the greatest waste of time since masturbation was discovered".
Welsh, who came to prominence in the age of techno and the Internet, is inevitably cooler about what happens to work when it is adapted, sampled and generally kicked about. There's so much digital chaff floating around, we are having to learn a new skill: working out what's actually worth digesting. (Some people still insist on being doggedly obtuse about the difference between print and online text. Janet Street-Porter, writing for the latest edition of a computer magazine, lambasts the Internet for being "emotionally unrewarding" because it "works by emphasising the solitary experience, away from human contact"; presumably she also has a big problem with books and jogging.)
You might expect the Internet, the tool of a new generation of readers and writers, to be bursting at the seams with material about a zeitgeist writer like Welsh, whereas Mailer, that desiccated old man of letters, would be all but absent. Far from it. The medium has already become too mainstream for any such obvious distinctions to present themselves, but there are differences.
Mailer's presence online is, as you might expect, rather staid. The New York State Writers' Institute has produced a comprehensive but fairly straightforward potted biography and a bibliography; unfortunately, it has no real feel for the freedom that the Internet can give. It's the sort of thing that could just as easily have been printed in a brochure.
Compare that with Welsh. His publishers, displaying an admirable understanding of the writer's natural constituency, have constructed a truly epic Trainspotting website. You'll recognise the site design immediately because it's the same as the film posters which have already become (the world being just a little too postmodern these days) transcendental classics. The site, however, is put together with a real passion. It has links for every subject in the Trainspotting universe from Iggy Pop to heroin-addict sites.
Some have already said that Welsh has moved on from being a writer to being something altogether different. He has already embraced the Ecstasy generation. My guess is that sooner or later the digital generation will follow.
Potted Norman Mailer biography
The trainspotting home page
Another Irvine Welsh page