How to identify web 2.0?

If a website can do the following then you can assume that it is a web 2.0:

• You can easily comment on, or preferably, actually change the content that you find on a Web site.
• You can label your information with tags and use them to find that information again.
• Your Web page doesn’t reload even once as you get a whole lotta work done.
• You are actively aware of other users’ recent activity on a site.
• It’s possible for you to easily share with others the information you’re contributing on the Web site.
• You can syndicate your information on a Web site elsewhere on the Internet through a feed like RSS or Atom.
• You can pick and choose the pieces of a Web site that you like and then add that functionality to your own site.
  
• There are easy ways to find out what content is the most popular or interesting at the moment.
• You heard about a new Web site because a friend enthusiastically recommended it to you out of the blue.
• There happens to be a mind boggling amount information and a lot of people on a site, yet it seems easy to find what you want and communicate with others.
• Everything you ever added to a given Web site can be removed easily at your whim.
• The Web site actively encourages you to share and reuse its information and its services with others.  And it even provides a license to do so.