I have to do an essay on impact of web 2.0 technologies on library and collection management? Please help. Is e-book an example of of web 2.0 technology?

Your question is very wide and it's hard to give you any definitive answers. When people talk about web 2.0 technologies in libraries they usually use the term Library 2.0 . Wikipedia has a nice article about Library 2.0. I think you should start by reading it. The article is full of references to other articles. You can find it here:
http://en.wikipedia.org/wiki/Library_2.0

E-book is not necesserily a good example of web 2.0 technologies. Web 2.0 usually refers to the services, which use user driven technologies and collaboration. E-book is not like that. It is just like a normal book in a new digital platform.