Also, global legislation is not necessary to effect change. Laws affecting one region can effect changes in all. For example; EU based companies are required to comply with EU law. They in-turn require their product suppliers to comply, wherever they are based, or risk losing their business.
If nothing else, the 'cookie law' has demonstrated this. Google, Yahoo & Disqus (among others) have changed their products in response to the law.
No, that would be addressing the problem at the server side, which is not quite what I had in mind.
Solving this on the client side means: The browser should make it as hard as possible for websites to track the user. Unless, of course, the user explicitly opts in to be recognized and tracked by this site (e.g. by registering and logging in).
Well, the latter might be working if enforced by every legislation in the world. But the former ensures it will never solve the problem: "Oh, this user explicitly asked us not to track her, so it might be especially interesting to track that one."
In other words: More work for white hats, less work for black hats.
I'd rather see this issue solved on client side. For instance, by improving the "incognito" mode of Chromium, combined with a law that protects operators of Tor end nodes.