Why is China's social network changing so fast?

ring k carefully at the Chinese and American social network development process,
in addition to the so-called Copy to China obvious mark,
we can also find an interesting phenomenon,
compared with their American counterparts,
seems to be very frequent replacement of China social network.
Since the Google of Microsoft step by step,
the Internet has appeared in the Facebook,
Youtube,
Twitter and other social class Internet companies,
which is now the giant company,
almost overnight in front of us.
In February 2004,
Facebook founded by Harvard University students Mark Zuckerberg Youtube,
a year later,
in 2005 2 years by Paypal Chad Hurley,
three former employees of Chen Shijun,
Jawed Karim created a year later,
Twitter released by Odeo in March 21,
2006.
Now,
ten years have passed,
Facebook,
Youtube,
Twitter three companies are still strong,
and showing a growing vitality,
has become a pillar of the global Internet industry.
Just as the Internet is surging,
social networking changes in Chinas Internet a