Nice Post Rey.

I think the key thing you need to consider is what is the end goal?

- Is it to get developers aware of something?
- Get developers using something?
- Get certain companies or industries using something?
- Is it to get partners who help generate a story to drum up further interest?

Based on that, you'll then have an idea of what you want to track and to some degree how you track it?

awareness - social media, conferences, podcasts and videos are good bets.
Use - This can be done by any means you can think of : crawl top 1000 sites and check implementations / growth of use, crawl github for use, ask developers to ping you with implementations
Companies / Industries - measure yes or no are they interested, yes or no did they implement.
Generate stories - Get partner interest and then generate story and interest. (Measure how you will, social, attendees of conferences, views on post etc).

From the list above, the outreach approach would be tailored to try and further that goal.

I agree with Todd's sentiments. Chasing numbers is one of the most de-motivating things I can think of for a developer advocate. Having and following metrics of implementations is good and you should have them to hand and should be used to review how / what kind of outreach should be done, but setting requirements on results feels somewhat counterintuitive to the goal of advocacy in my head.