Here is a tabulated "compare and contrast" of Web usage patterns 1.0, 2.0, and 3.0.

  Web 1.0 Web 2.0 Web 3.0
Simple Definition Interactive / Visual Web Programmable Web Linked Data Web
Unit of Presence Web Page Web Service Endpoint Data Space (named structured data enclave)
Unit of Value Exchange Page URL Endpoint URL for API Resource / Entity / Object URI
Data Granularity Low (HTML) Medium (XML) High (RDF)
Defining Services Search Community (Blogs to Social Networks) Find
Participation Quotient Low Medium High
Serendipitous Discovery Quotient Low Medium High
Data Referencability Quotient Low (Documents) Medium (Documents) High (Documents and their constituent Data)
Subjectivity Quotient High Medium (from A-list bloggers to select source and partner lists) Low (everything is discovered via URIs)
Transclusence Low Medium (Code driven Mashups) HIgh (Data driven Meshups)
What You See Is What You Prefer (WYSIWYP) Low Medium High (negotiated representation of resource descriptions)
Open Data Access (Data Accessibility) Low Medium (Silos) High (no Silos)
Identity Issues Handling Low Medium (OpenID)


Solution Deployment Model Centralized Centralized with sprinklings of Federation Federated with function specific Centralization (e.g. Lookup hubs like LOD Cloud or DBpedia)
Data Model Orientation Logical (Tree based DOM) Logical (Tree based XML) Conceptual (Graph based RDF)
User Interface Issues Dynamically generated static interfaces Dyanically generated interafaces with semi-dynamic interfaces (courtesy of XSLT or XQuery/XPath) Dynamic Interfaces (pre- and post-generation) courtesy of self-describing nature of RDF
Data Querying Full Text Search Full Text Search Full Text Search + Structured Graph Pattern Query Language (SPARQL)
What Each Delivers Democratized Publishing Democratized Journalism & Commentary (Citizen Journalists & Commentators) Democratized Analysis (Citizen Data Analysts)
Star Wars Edition Analogy Star Wars (original fight for decentralization via rebellion) Empire Strikes Back (centralization and data silos make comeback) Return of the JEDI (FORCE emerges and facilitates decentralization from "Identity" all the way to "Open Data Access" and "Negotiable Descriptive Data Representation")

Naturally, I am not expecting everyone to agree with me. I am simply making my contribution to what will remain facinating discourse for a long time to come :-)