What KPI' s should be used to measure a B2B website' s performance?

I run several website for a B2B group but they have no web KPI's in place. I look at visitor/new visitor splits - engine referral levels, and numbers of subscribers but am I missing another dimention here?

What is a VPN?

VPN is (Virtual Private Network) were first used by companies to enable their employees to securely access internal systems such as email remotely (e.g. from home or while on business trips). Today they are increasingly being used for personal use by individuals to protect their privacy while online in public places (e.g. when using the wi-fi connection in a cafe) or in a country where the internet is censored / blocked (e.g. China, Saudi Arabia��).