30 Seconds of Knowledge - Become a better developer, in every new tab.
Product School - The global leader in product management training
Random User-Agent - Automatically change the user agent after specified period of time to a randomly selected one, thus...
The Product Folks - A volunteer-led community of product managers and makers
know/how Product Managers - A weekly newsletter with 5 practical tweet-length PM tips
Software Product Management Stack - Resources & tools to help you manage your software product