Jason Kolb (who initially nudged me to chime in), and then ReadWriteWeb, and of course Nova's Twine about the topic, have collectively started an interesting discussion about Web.vNext (3.0 and beyond) under the heading: The Future of the Desktop.

My contribution to the developing discourse takes the form of a Q&A session. I've taken the questions posed and provided answers that express my particular points of view:

Q: Is the desktop of the future going to just be a web-hosted version of the same old-fashioned desktop metaphors we have today?
A: No, it's going to be a more Web Architecture aware and compliant variant exposed by appropriate metaphors.

Q: The desktop of the future is going to be a hosted web service
A: A vessel for exploiting the virtues of the Linked Data Web.

Q: The Browser is Going to Swallow Up the Desktop
A: Literally, of course not! Metaphorically, of course! And then the Browser metaphor will decomposes into function specific bits of Web interaction amenable to orchestration by its users.

Q: The focus of the desktop will shift from information to attention
A: No! Knowledge, Information, and Data sharing courtesy of Hyperdata & Hypertext Linking.

Q: Users are going to shift from acting as librarians to acting as daytraders
A: They were Librarians at Web 1.0, Journalist at Web 2.0, and Analysts in Web 3.0 (i.e, analyze structured and interlinked data), and CEOs in Web 4.0 (i.e. get Agents to do stuff intelligently en route to making decisions).

Q: The Webtop will be more social and will leverage and integrate collective intelligence
A: The Linked Data Web vessel will only require you to fill in your profile (once) and then serendipitous discovery and meshing of relevant data will simply happen (the serendipity quotient will grow in line with Linked Data Web density).

Q: The desktop of the future is going to have powerful semantic search and social search capabilities built-in
A: It is going to be able to "Find" rather than "Search" for stuff courtesy of the Linked Data Web.

Q: Interactive shared spaces will replace folders
A: Data Spaces and their URIs (Data Source Names) replace everything. You simply choose the exploration metaphor that best suits you space interaction needs.

Q: The Portable Desktop
A: Ubiquitous Desktop i.e. do the same thing (all answers above) on any device connected to the Web.

Q: The Smart Desktop
A: Vessels with access to Smart Data (Linked Data + Action driven Context sprinklings).

Q: Federated, open policies and permissions
A: More federation for sure, XMPP will become a lot more important, and OAuth will enable resurgence of the federated aspects of the Web and Internet.

Q: The personal cloud
A: Personal Data Spaces plugged into Clouds (Intranet, Extranet, Internet).

Q: The WebOS
A: An operating system endowed with traditional Database and Host Operating system functionality such as: RDF Data Model, SPARQL Query Language, URI based Pointer mechanism, and HTTP based message Bus.

Q: Who is most likely to own the future desktop?
A: You! And all you need is a URI (an ID or Data Source Name for "Entity You") and a Profile Page (a place where "Entity You" is Describe by You).

One Last Thing

You can get a feel for the future desktop by downloading and then installing the OpenLink Data Explorer plugin for Firefox, which allows you to switch viewing modes between Web Page and Linked Data behind the page. :-)