what is the most famous community site?
(web2.0 related sites)

Web 2.0 has many problems with 'definition'.

According to Wikipedia, http://en.wikipedia.org/wiki/Web_2.0, it is:

Web 2.0 is a phrase coined by O'Reilly Media in 2004 to refer to a
supposed second-generation of Internet-based services that let people
collaborate and share information online in new ways ? such as social
networking sites, wikis, communication tools, and folksonomies.
O'Reilly Media, in collaboration with MediaLive International, used
the phrase as a title for a series of conferences and since then it
has become a popular, though ill-defined and often criticized,
buzzword amongst the technical and marketing communities.

Many find it easiest to define Web 2.0 by associating it with
companies or products that embody its principles. Tim O'Reilly gave
examples in his description of his "four plus one" levels in the
hierarchy of Web 2.0-ness:[1]

    * Level-3 applications, the most "Web 2.0", which could only exist
on the Internet, deriving their power from the human connections and
network effects Web 2.0 makes possible, and growing in effectiveness
the more people use them. O'Reilly gives as examples: eBay,
craigslist, Wikipedia, del.icio.us, Skype, dodgeball, and Adsense.
    * Level-2 applications, which can operate offline but which gain
advantages from going online. O'Reilly cited Flickr, which benefits
from its shared photo-database and from its community-generated tag
database.
    * Level-1 applications, also available offline but which gain
features online. O'Reilly pointed to Writely, gaining group editing
capability online and iTunes because of its music-store portion.
    * Level-0 applications would work as well offline. O'Reilly gave
the examples of MapQuest, Yahoo! Local, and Google Maps. Mapping
applications using contributions from users to advantage can rank as
level 2.

Thus, according to Wiki and following O'Reilly definition of Web 2.0
Level 3 you would find these sites : eBay, craigslist, Wikipedia,
del.icio.us, Skype, dodgeball, and Adsense.

Now, of course, this answer is very North American centric and there may by others.

canadianhelper
thank you very much..
your writing is helpful for me.

thank you..