Next time you go online, you might give a little thought about what it means to a test subject. Our entire online lives have become one big survey: We're talking about A/B Tests. That's where Internet companies monitor and record our clicking habits to optimize our "experience," and to gauge their success at selling us products. There is an upside to A/B testing, but Zócalo Public Square columnist Joe Mathews says the practice of treating everyone as a lab rat is also fraught with privacy concerns and thorny ethical questions.