Wow, that's a great summarization of all the persistence technologies available.
I found the stats at the end to be deceptive though. You'd have to code support for 3 different native client storage APIs in JavaScript + use Flash in order to cover enough users to rival cookies. It's no wonder most web devs just use cookies.
The end result isn't an alternative with a 1% gain over cookies. The end result is a system that writes & reads to all possible data stores available simultaneously. The gain from that is a site where an "always logged in" can be potentially much, much longer.
There are still a large number of people who have terrible problems managing web site logins. Reducing the barriers to using your site for returning visitors is definitely a goal with a lot of value and clear ROI.
I found the stats at the end to be deceptive though. You'd have to code support for 3 different native client storage APIs in JavaScript + use Flash in order to cover enough users to rival cookies. It's no wonder most web devs just use cookies.