My number one metric is my phone.
It rings and someone says:
"I read on the web that you ... Could you do this and this for me?"
And then they threatem me to give me money if I help them.
I usually oblige.
And I start to worry when my pageviews on my blog go down and write some more good articles that some people link and hype and that make other people call me.
OK, most send E-Mail, but when those are 'caught' that se the phone, I know I won ;)