For those interested in changing the amount of storage per domain in firefox: about:config -> dom.storage.default_quota. Also, dom.storage.enabled to change whether you use local storage at all or not. I don't know if chrome or iexplore also give those options.

It's nice that this exploit is presented openly as a proof of concept, and includes a button to undo the damage. Many people, upon finding this, would try to use it for shadier ends.