Ars Technica on why blocking ads hurts the websites that you visit:
There is an oft-stated misconception that if a user never clicks on ads, then blocking them won’t hurt a site financially. This is wrong. Most sites, at least sites the size of ours, are paid on a per view basis. If you have an ad blocker running, and you load 10 pages on the site, you consume resources from us (bandwidth being only one of them), but provide us with no revenue.