The real hassle with adblocking is when you're counting on ad revenue to run a business.
But honestly, the bottom line is very much there even with adblocking. I know people visiting my client sites adblock at a fairly high rate, and I don't completely blame them.
If everything is being managed correctly, a simple header-footer ad arrangement returns nearly 10:1 over the cost of hard drive space and bandwidth. If a business can't make ends meet on that, they either are too small of a scale, or are wasting large sums of money elsewhere.
I actually show a higher return per unit cost giving away hosting than I do selling it. It's all in what kinds of content you have, and how it is presented.
But once again, because big business can't handle playing by the rules and treating the end user with respect, the little guy gets shafted and has to deal with users conditioned to either ignore or block ads.
What really irks me is I have multiple times told the advertising networks text and images only. No flash, no sound. And every time I turn around I'm seeing one of those stupid blinky noisemaking flash ads in my rotation, irritating my clients as much as it irritates me. A few times as well I've observed malware in ads too, although when I find one of these I usually flag it with the advertiser so it gets pulled down.