First, it is not clear if a web "surfer" is in a contractual relationship with a random site s/he visits in a way that a Blizzard gamer is (by the virtue of buying the game and clicking through the TOS). Second, Blizzard game bots use a part of the company's codebase, where the ad blocker works solely in my own browser. They do not rely on proprietary code that belongs to someone else. Finally, where the Blizzard bot…
Excellent point, I think what we may see is that adblocker are perfectly legal, but those lists of ad sites to block, not so much.
Ad blockers with tor, bittorrent and rss capabilities coming soon may be headed our way soon.