I’ve been struggling for days to put into words my reaction to the launch of Google Buzz. But the phrase I can’t get out of my head is “HOW could they screw up THIS MUCH?”

Well here’s how: Google took Gmail, one of the most widely used web services on the planet, and modeled a quantum change in its behavior with an insulated, private, corporate, top 1% tech-savvy user base.

Google Buzz creates an instant social network based on your email history. Google engineers wrote an algorithm to analyze years of correspondence in users’ Gmail accounts. At launch, by default, these associations were automatically linked and shared with everyone else in your "network." [Google has already modified the default behavior twice in response to criticism].

Apparently, Google tested Buzz internally for months prior to public launch last week. Unfortunately, the controlled conditions of corporate email are a poor stand-in for conditions “in the wild” of a public email service.

You could imagine that the post-launch backlash could have been anticipated with a bit of forethought, even an afternoon meeting that went something like this:

AGENDA 1. What types of people use Gmail? 2. What do they use it for? Who do they communicate with and why? 3. Does our internal beta account for those types of uses? 4. If not, how do we introduce this service to people who aren’t like us?

At a bare minimum, identify a set of people who represent a cross section of users: A grandparent who switched from AOL; a high school junior with an active and evolving social circle; a struggling factory worker in a hostile political environment; a professional with a secretive private life.

Then, just as a sanity check, ask “Is there anything problematic with mining the history of their person-to-person emails and creating a single transparent group from that list?”

For many things, Google’s approach—develop, internal beta, release, measure, adjust—is an adequate way to stumble towards a better experience. That approach takes good ideas, puts them in play, then sands down the rough edges and suggests enhancements. For something as significant as combining email and social networking, it’s toxic.