Product School - The global leader in product management training
30 Seconds of Knowledge - Become a better developer, in every new tab.
The Product Folks - A volunteer-led community of product managers and makers
Random User-Agent - Automatically change the user agent after specified period of time to a randomly selected one, thus...
The Product Management guide - A book on how to create and ship products that people love
know/how Product Managers - A weekly newsletter with 5 practical tweet-length PM tips