know/how Product Managers - A weekly newsletter with 5 practical tweet-length PM tips
Nifty - Manage projects, work, and communications in one place.
Dash for Tumblr - Easiest way to learn to build Tumble themes
Intercom on Product Management - The ultimate resource for aspiring product managers
Blockcred - Preventing academic credential fraud through the Blockchain.
productboard - Beautiful and powerful product management.