1. Drawbacks of Traditional Web
Web pages were mostly static HTML pages
Users were just consumers
For user feedback / comments, usually guest book page was provided
Content usually served from file system instead of RDBMS
Frames / Tables to position or align elements
<blink> / <marquee> tag for animation
Synchronous communication

2. Web 2.0 Characteristics / Features
User generates data / provides data [eg: google maps]
Creation of user accounts / profiles
Users categorize information by tagging
Users act as police
Users add value to applications as they use it [ eg: youtube / facebook, etc.,]
Rich user experience
Asynchronous communication
Cloud computing
scalability

3. Folksonomies
Software As a Service (SaaS)
Data is King
Convergence [eg: web content on TV / TV content on PC
Iterative development
Rich Browser Experience [eg: draggable grids, animated charts, etc.,]
Multiple Delivery Channels [eg: internet content delivered using WiFi, Bluetooth / cellular phones, Tabs, etc.,]
Web Services / Hosted Services
Mashups
Rise of individual developers
Dispersion [eg: file sharing done using limewire/ edonkey/ 4shared.com / bittorrent / dropbox, etc.,]

4. Examples of Web 2.0 Social networking sites
Self publishing platforms [ eg: blogs like wordpress, instagram, tumblr, etc.,]
Tagging for categorising
Social bookmarking [ eg: delicios.com, stumbleupon.com, etc.,]
Wikis
Video sharing sites [ eg: youtube, etc.,]
Websrvices [ eg: google services, facebook services, twitter services]
Podcasting
Webcasting
RSS (Rich Site Summary)
Crowd sourcing
Web content voting

5. Technologies Client Side:
Ajax, Dojo, Jquery, etc., (Javascript Libraries)
XMLHttp
Flex
Silverlight
Widgets for chart / animation [eg: clock, calendar, etc.,]
XML
JSON
Plugins
Extensions

6. Server Side:
Servlets
JSP
ASP.Net
PHP
Ruby, etc.,
Communication:
SOAP
REST
UDDI