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...
know/how Product Managers - A weekly newsletter with 5 practical tweet-length PM tips
Better Product Manager - Experience the life of a PM through these tests
Chameleon WebExtension - Chameleon is a Firefox extension to Spoof your browser profile.