How often updating?

base is updated every 3 hours

Can I get all of the proxy server a text file?

Yes, but is a paid opportunity

What does the option "Charged" means?

This parameter is calculated using a special algorithm, and means the evaluation of health proxy
         whole. The higher the number, the better.

How different levels of anonymity?

"Transparent Proxy" - conveys your real IP address and shows that you are using a proxy.
"anonymous proxy" - do NOT share your real IP address, but it shows that you are using a proxy.
"Elite Proxy - DO NOT transmit your real IP address and does not show that you are using a proxy.