There is an easy way to win over "the fast web" without shutting everything down. It's easy and boils down to understanding how reinforcements work. The most addictive and enjoyable reinforcements are random reinforcements, both for humans and animals (see B. F. Skinner's work for reference). If you don't want to get addicted then make your rewards less random by for example checking your email, HN etc. two/three times a day in predictable patterns.

Personally, I use SelfControl. When I want to do serious work I fire it up and block everything for 1-3 hours. This works wonders for my productivity and it also regulates addictiveness. I don't know if this makes me part of the "slow web" movement, I just don't like distractions.