It doesn't as others have pointed out. AdBlock+ just happens to have been advertised well. (How ironic!) Ad blockers usually are on a proxy (junkbuster, privoxy, etc.) which can be integrated into caching proxy which is often integrated into a router. This type of set-up works best but keep in mind some people actually want to see the ads, at least some of them. Like a spam blocker, the user must have the final say. Its a good idea to play the ads into '/dev/null'. If everyone did that, this whole "controversy" is moot.
This whole topic is a bit troll, IMO. Beating ad blockers is a matter of running ads locally, on the site itself. "Targeted advertising" is a bad idea in all respects. 'Malware' often comes from going to rogue sites. Using an easily hacked targeting service is risking much ill-will from your users.
At the user end, its probably best to keep this material away from your system. While 99% of all problems of this sort stem from using a certain operating environment, being 100% safe is a false idea. Running a browser in a virtual
environment is 'virtually' 100% safe. That isn't exactly 'home technology' yet, but a number of /. readers probably use it.
Most users should block ads. True, its nice to know what pressures the site is under and many people let the ads through only for that reason. Ads from the site itself are generally of a higher quality, though stopping animations is essential for me to read the text. (Not sure how common that is.) Since when has Youtube put ads in the videos? Sure, "half of the videos" are ads of one sort or another but I choose to see them.