Garbage in, garbage out isn't usually about garbage. Usually.

I'm going to share a private post, but since I was the original author of the private post in question, I guess it's OK. In addition, the fact that this post was "privately" shared with over 2,000 people lessens the impact of its privacy setting.

I wrote this back in January on Google+:

Garbage in, garbage out.

Google+ just suggested that I invite my father to join Google+, because it had access to his email address.

Unfortunately for Google+, my father died a couple of years ago.

I really need to clean out my old email addresses.

The phrase "Garbage in, garbage out" (abbreviated as GIGO) is one that you often hear in the tech world, and refers to the practice of drawing conclusions from data that is faulty. In this example, Google extracted a list of email addresses and figured that since these addresses were stored with my data, I'd want to invite these people to join Google+. Google simply grabbed the addresses, not realizing that at least one of those people was never, ever, ever going to join Google+.

Of course, when we use the phrase "garbage in, garbage out," we're not talking about real garbage. We're talking about data that isn't useful.

But what if "garbage in, garbage out" actually involved real garbage?

Stay tuned.