To find the "feeling" about web 2.0

I am looking for the special feeling for the web 2.0. I compared the flickr from yahoo and picasaweb.google.com. The picasaweb should use the ActiveX and this is not comfort for me, but, i found the basic uploader that is a normal web file uploader page. Actually the flickr is more complex for the images dealing, like resize and more functions.