The Product Manifesto - Product Managers face the biggest challenges of our day, which is why our community needs a common set of product principles.
Intercom on Product Management - The ultimate resource for aspiring product managers
userinput.io - Get on-demand feedback for your app, website or idea. Learn how to improve by hearing real opinions.
Product School - The global leader in product management training
ithinki - A simple user feedback tool for start-ups
Product Management Exercises - A repository of product manager job interview exercises