What is Web 2.0?

Answer 1

The next generation of the internet. Faster, more intuitive, etc.

Answer 2

The term Web 2.0 refers to a second generation of services available on the World Wide Web that lets people collaborate and share information online. In contrast to the first generation, Web 2.0 gives users an experience closer to desktop applications than the traditional static Web pages. Web 2.0 applications often use a combination of techniques devised in the late 1990s, including public web service APIs (dating from 1998), Ajax (1998), and web syndication (1997). They often allow for mass participation (web-based social software). The concept may include blogs and wikis.

Answer 3

In these days many people speaking about Web 2.0 Like many important concepts, Web 2.0 doesn\'t have a hard boundary, but rather, a gravitational core. You can visualize Web 2.0 as a set of principles and practices that tie together a veritable solar system of sites that demonstrate some or all of those principles, at a varying distance from that core.
In terms of building applications for Web 2.0, I believe the key underlying theme is the separation of data and user interface through open data formats, RSS/Atom feeds, (in fact the semi structured data in XML format) and programming interfaces made publicly available. This enables not only a revolution in machine to machine communication, as all the excitement about web services has been about, but also human to machine as we\'re seeing with remixing applications and new user interfaces on data. It\'s also no accident that scripting languages such as PERL, PYTHON, PHP, and now Ruby, play such a large role at web 2.0 companies. Dynamic languages (often called scripting languages and looked down on by the software engineers of the era of software artifacts) are the tool of choice for system and network administrators, as well as application developers building dynamic systems that require constant change. And Ajax and Flash we have the outstand role for doing this.
But I consider that providing easily access the Web services is the real power of the Web 2.0 era.
In Web 1.0, a small number of writers created Web pages for a large number of readers. Anyone can build an interface to content on any domain if the developers there provide a Web services API. This is a great power no?
Important characteristics of web 2.0
Business aspects:
• Affiliation
• Cost per click
• Data Inside
• Data Driven
• Page Rank
• Perpetual Beta
• Recommendation
• Search Engine Optimization
• Trust
• The Long Tail
• User Centred Design
• Venture Capital

Technical aspects:
• AJAX
• Flash (with also the freeware variants called generic Flash OS )
• Aggregation
• Audio, Video
• CSS Design
• XHTLM and XML
• Granularity
• Micro formats
• Mobility
• Modularity
• OpenAPIs
• RSS
• Ruby on Rails
• Syndication
• Semantic
• SOAP
• REST
• Web Standards
• Wifi, UMTS
• FOAF, XFN
Social Aspect:
• Accessibility
• Blogs
• Collaboration
• Focus on Simplicity
• Folksonomy (Tagging)
• Instant Messaging
• Joy of Use
• Liveliness

Answer 4

Take a look here:

http://en.wikipedia.org/wiki/Web_2.0