Just read on the GPC Press Release site that Google is starting work on a new open source platform enabling all of its online apps to have offline capabilities. Sounds intriguing.
Google Gears marks an important step in the evolution of web applications because it addresses a major user concern: availability of data and applications when there’s no Internet connection available, or when a connection is slow or unreliable. As application developers and users alike want to do more on the web—whether it’s email or CRM or photo editing—enhancements that make the browser environment itself more powerful are increasingly important.
Source: Google Press Center: Press Release
You can access Google Gears here.