We’ve told you before that Millennials are turning to new tools that let them harness their own data for their own personal benefit and enjoyment. The new app Pplkpr (pronounced “people keeper”) does just that, using a combination of tracked body metrics and self-reporting to determine which friends make users happy, and which have a negative impact on them. Using a Bluetooth heart rate monitor, the app measures physical response while one is hanging out with friends, learning over time which friends create anxiety, boredom, excitement, and concluding whether or not a friend is toxic. The app’s creators say Pplkpr was created partly as a criticism for the decisions we allow data to make for us, but there is clearly some interest around the idea. (Huffington Post, Mashable)