So why do people disable cookies? I assume that it is out of some desire to deny information to advertisers. I guess they find it annoying to have advertisements that better target them? :)

And what is the reasonable replacement for a cookie (or two) here? Certainly, I could add custom CSS to hide such bits. But browsers don't make it easy to add custom CSS in my experience (nearly the opposite). And browsers don't let the site make suggestions of CSS to add for the user so such a solution is significantly less useful in not being able to be offered to the user with a simple click.

I have practical reasons for disabling javascript. I'm sure there are people who disable cookies. I'm sure there are a lot of people who have tools that disable certain kinds of cookies (trying to focus on cookies used by advertisers). But I've heard a lot of arguments against disabling anonymous posting at PerlMonks and I don't think that "I refuse to accept any cookies!" has come up much at all.

In any case, if somebody routinely refuses cookies, it seems reasonable to me to allow them to decide to accept some cookies that are very clearly only there to let them customize a couple of features (no "tracking number" included) or to not accept them and take on the burden of rolling their own customization.