Keynote -- What is the Web's model of computation?

The keynote was given by Luca Cardelli. As testified by a summary of the main points below (recorded by Dave de Roure) it is not altogether clear what exactly is the Web's model of computation, nor what support should be provided on a language level or API level.

There is concept of "global computation" (eg crawlers) but...
Web is not uniform (except HTTP)
Speed of light is finite => mobility a necessity
Single global structure not enough, view as multiple "global computers" ("intrawebs", maybe non
HTTP, non-Java-VM) each with some guarantees
model of computation = language independent model for APIs + model on which to base language constructs
turn web into uniform structure or "program the complexity" (yes)?
existing programming models don't capture locality
observables like referential integrity and QoS not in trad. models
Different languages may be appropriate for different "global computers" e.g. Telescript, Obliq, Java
Semantics needed to understand computational assumptions and requirements, answer important security questions, reason about programs
Issues: Typing (MIME is a mechanism...?), security, reliability, modularity, resource management

See http://www.research.digital.com/SRC/personal/Luca_Cardelli/home.html for more material.

The slides are available at (A4) http://www.research.digital.com/SRC/personal/Luca_Cardelli/Slides/WWW5APITalk.A4.ps
(USLetter) http://www.research.digital.com/SRC/personal/Luca_Cardelli/Slides/WWW5APITalk.ps

In particular, Cardelli's speech made clear that the distinction between API, languages and computation models is not clear cut.