Blogging
Blogging took the concept of private diary and made it public. You could consider any online space where personal views are expressed to be a blog,and this dates back to the BBS and usenet days. even yahoo! geocities, launched many blogger. This meant that people needed to make their own sites and know HTML coding. with the launch of open diary and live journal around 1998-99, people had access to easy to use tools to create thier own blogs.
Blogging was popular, that it prompted google to buy  blogger in 2003. After that many ways were introduced for blogging some of them are photo blogging, video blogging, audio blogging micro blogging and mobile blogging. So, if you are a good administrator and if you have good talents you can also blog in. The major use of blogging is that apart from the unearthing subject matter experts that you never knew existed , It is also a valuable source of income.
WIKIPEDIA :
wikipedia is a completely community driven initiative that met unquestionable success. Ever since it is launched at 2001, wikipedia has grown in popularity to now become one of the top 10 global sites. The concept was brilliant, an encyclopedia created anjd managed by a community, in a wiki format (editable by anyone). Wikipedia gets its fair share of criticism, based on the fact that anyone can edit any page and that popular opiion, rather than the 'right' information always prevail.
YOUTUBE :
In early 2005, when everyone wants network or blog. Youtube was a refreshing change There are an estimated 85 million videos on Youtube, and with all that streaming video content. it's estimated that the band width cost for video content, it's estimated that band width cost for youtube would be to call it community TV, where you can find content from almost every topic you can thinkl of. So popular was this inter video phenomenon that google just have to own it. In november 2006, Google coughed up $1.65 billion in stock to acquire youtube. That's Rs.6,600 crores, plus the Rs 4crore a day in bandwidth costs!