On August 29, 2018, we released STACK version 4.16.270. Included in this software update was the following:
Login to your STACK Account with Facebook
o If your Facebook and STACK account use the same email they will automatically be merged. o If you don’t have a STACK account that matches the email used with Facebook then you’ll get a new, empty, account. o More information on social sign-in is here: https://www.stackct.com/help/integrations/social-sign-in