>>Yes, storing data permanently on the client is generally a bad idea. However, storing temporary (cached) data such as lookups for increased speed; storing data locally while disconnected, and storing data locally for buffered cursor manipulation are at least three use cases for local storage that I can think of right of the bat. Hit the server as little as possible -- only when you need additional data or when you are ready to commit changes.
>
>it's never easy for me to switch from a development paradigm to another ...
>FoxInCloud leaves all data manipulation on server, client only deals with presentation via HTML & AJAX, never loads or sends raw datasets ...
>- lookups : AJAX incremental search / autocomplete limits data to retrieve
>- disconnected : why not, though requires moving some part of business logic on the client
>- buffered cursor : FoxInCloud does that on the server

Mostly that makes sense to me, especially the AJAX part with lookups. Local buffered cursor is nice if you have to do a bunch of searching, sorting, filtering, temporary indexing, setting relations etc. Having those things happen locally takes some load off the server and, maybe more importantly, reduces network traffic, I would think.

Mobile seems to be the future of computing, and network traffic restrictions on mobile devices are becoming a huge pain point here in the U.S. now that AT&T has moved to metered data service, and looks like Verizon will follow suit next year. As a result, programs on mobile devices must go on a serious bandwidth diet, and that's where local processing comes handy. With it you have only two contact points to the server: load once from the server, process all you want locally, commit changes once to the server.

Disconnected processing is one of those "would-be-nice-but-not-must-have" -features for most end users. There is something to be said for being able to work on your database while you are on a long flight or at some remote ski hut. There is also something to be said for not working ***all the time***, like while being on a long flight or at some remote ski hut ;-)