I'm totally amazed by 500 acquaintances that you've met and got in FB network and actually allow this networking.

Just how long (and lucky) will you remain if senior family generation never gets into FB networking?
Ok. If I include my 100+ relatives in North America who can read English, not the ones who are Chinese-language literate only (Forget about relatives in China, I can't read Chinese.), plus friends I still keep in touch, cycling acquaintances here that would be under 250.
If I included work colleagues (heaven forbid), that would amount to 500..over last 10 yrs.