Word Web 2.0 :

1. Is Web2.0 something new and different or just something that grows from Web1.0?

I know about Web 1.0 from O'Reilly article "What Is Web 2.0", I think that Web 1.0 was born with Web 2.0. If we type the phrase "Web 1.0" in a google search box , the first result will be "O'Reilly What Is Web 2.0". Now we do a search in wikipedia, when we type "Web 1.0", will see "Web2.0" and "(Redirected from Web 1.0)"

Which came first, the chicken or the egg? And the answer is: both came in the same time...i.e.both names appears in the same time

And the answer for the main question is:
It's like a child (Web 1.0) became a teenager (Web 2.0).

2. What exactly is Web 2.0? What is definition of Web 2.0?

Web 2.0 is a next step in creating web based services. Dynamic information provided and managed by the web services and created by the users and other services...
(the web as a platform)

Examples: blogging, Google (search results, services, adsense), wikipedia, flickr, de.li.cio.us, etc..

The web is a platform (operating system), and the web services are applications ...

3. What more should I know about Web 2.0, if I want to dig deeper in this subject?

Folksonomy, Tag clouds, Social bookmarking, Rss, Syndication, Blogroll, Permanent Link, PageRank, Perpetual Beta, AdSense, Ajax, XML, RDF, Wiki, CSS, XHTML, Creative Commons, Web 3.0, Semantic web, Social networking, and so on... Lots of slogans, labels, names...

4. Where should I look for Web 2.0 based websites?

Anywhere where people making and sharing their works, thoughts, opinions, knowledge especially these websites where content has been changing dynamically and where you can create new content. (ex. blogs, social bookmarking services, online photo albums, etc).

5. What isn't Web 2.0 ?

Maybe these websites, where people can't do more than reading, watching or browsing through content aren't conform the new concept of Web 2.0, however this is very general definition. I think, we can not tell that something is hundred percent Web 2.0 or hundred percent Web1.0. If something isn't widely open for people and don't have social resources isn't Web 2.0 ready...