In-browser Redis
narma.github.io
narma.github.io
(Also, it is useful to bring anonymization to the masses)
Most of these "try X" features need a user session, allocate a server-side component to that session and then manage recycling. It's much less expensive to stick a JS on a CDN, and also scales much easier horizontally.
var Redis = {};
;)
s/;)/:trollface:/ ;)
Using it as slave of a server side redis would be fun. :)