[homakov]

not amount, but total Length of the Cookie header. Otherwise number of cookies will be ~5.

Yes I recall filldisk.com, but that one doesn't seem harmful to user (he knows where it comes from & exploit is quite slow).

Cookie bomb can "bomb" some exact path, so the trick has many uses. E.g. you can "block" /dont_like_this_post on blogspot entirely, while the rest of Blogger will work.