Way back in the "Central" days "occasionally connected" were the buzzwords that were used to describe apps that were aware of when they had Net connection and therefore allowed the user to work online/offline seamlessly (or almost anyway).
The rumors of Apollo also seem to be continuing this trend, in that it will allow Flash developers to create desktop apps that are capable of being "occasionally connected".

So.. with that in mind, take a look at Scrybe. From the video it looks like it's totally browser based (not an Apollo app) and has some really interesting features.

(firefox didn't catch the typo in that title, eh? hehe..)