Wikipedia
MicroID
MicroID is a decentralized identity protocol. It was originally developed in 2005 by Jeremie Miller 1. A MicroID is a simple identifier comprising a hashed communication/identity URI (e.g. Email, OpenID, and/or Yadis) and claimed URL. Together, the two elements create a hash that can be claimed by third party services.
Ben Laurie demonstrated privacy problems with it in 2006 , as did Chris Erway in a Brown CS Technical Report in 2008