very good write-up. What you mentioned is totally true.
I don't see SNS as a huge advancement in technology and website format, it
is more like a re-packaged BBS forum or blogsphere.
So, it is an existing product rather than a new invention.
For existing product, the execution matters a lot. More like opening a
grocery store, it is not the technology but the good execution and marketing
, will make it successful.
2 cents again, hehe