What is Web 2.0?

What is Web 2.0, should you build a web 2.0 site and what are the benefits or downfals?

Web 2.0 is a term describing the trend in the use of web design which is aimed at improving and enchasing user experience, information sharing, greater user integration, creativity and so on...
Web 2.0 reffers to how website developers create websites and how end users use it.

In the opening talk of the first Web 2.0 conference, O'Reilly and John Battelle summarized what they saw as the themes of Web 2.0. They argued that the web had become a platform, with software above the level of a single device, leveraging the power of the "Long Tail", and with data as a driving force.

In basic user terms web 2.0 means a website that integrates text, images and application into one whole as a better way of representating the websites and greater end user experience.
On a more high level web 2.0 is reffered to as a business revolution in the computer industry and more specificly the internet, however this is arguable as every component of web 2.0 has previosly existed although may not have been used in such ways!

WEB 2.0 website
Some examples of web 2.0 websites are: ebay, flickr, wikipedia, skype, microsoft, etc...
Web 2.0 aims at improving WWW technologies such as RSS feeds, blogs, API's and so on...
Some web 2.0 integration examples are social networing sites, google maps, delicious, etc...

O'Braily's web 2.0 example:

DoubleClick-->Google AdSense
Ofoto-->Flickr
Akamai-->BitTorrent
mp3.com-->Napster
Britannica Online-->Wikipedia
personal websites-->blogging
evite-->upcoming.org and EVDB
domain name speculation-->search engine optimization
page views-->cost per click
screen scraping-->web services
publishing-->participation
content management systems-->wikis
directories (taxonomy)-->tagging ("folksonomy")
stickiness-->syndication

Is it worth developing web 2.0?
You may not even be aware of it but you may already have a web 2.0 website, but in a more global view your site is only part of the so called web 2.0.
Web 2.0 site means innovative site with lots of end user enchased experience like custom user profiles, users having personal blogs on your website or in any other way connecting them.
Another thing is integration between text, images and application into 1 whole for enriched user experience.

Benefits or downfals?
If I'm to answer I'd say web 2.0 is nothing more than the natural evelution of the web and can't be seen as a different type of WWW(world wide web)experience or any other way it may be called that didn't already exist.
In order for some definition to explain web 2.0 it must have evolved from something and portraited some different characteristics from what has been up to that point.
Instead I look at "web 2.0" as a continued evolution path for websites and online experience which has been named web 2.0 that can't be characterized or claimed to be something special.
In the end you should go and try build a website that you think is good for you, your business, users or any other thing you build your website for!