The fantastic thing is Brad Neuberg’s Dojo work means we can code independently of the local storage mechanism. Since IE also has local storage, as well as Flash, most bases are covered, or soon will be: Anyone with EITHER IE or Firefox or Flash will have local storage. (Incidentally, we had a discussion in the comments on Ajaxian about the possibility of S3 and other remote bindings as well, which I’m guessing Brad will implement at some point.)
But what I’d like to know, what I’d really really like to know, are the limits for these various techniques (I think Flash is 10MB per domain, right?)
As I’ve said before, there are valuable applications of massive storage - hundreds of gigs, e.g. media players that store data server-side, but cache content locally to cut down on the need for streaming from the server. Hopefully, these storage technologies won’t try to second-guess the imagination of web developers by setting a dumb arbitrary limit that “no-one would ever need more than”, like 100MB or 1GB or whatever.
If there’s room on my hard drive, and I trust the domain, let me store as much as I please.