Hacker News on 13 January 2020

• iOS 13 app tracking alert has dramatically cut location data flow to ad industry
• Show HN: I wrote a book for engineers that want to become engineering managers
• Why I Keep a Research Blog
• Visa Buys Plaid
• Language Learning with Netflix extension
• How to Invest in Startups
• 1195725856 and other mysterious numbers
• Mercurial’s journey to and reflections on Python 3
• The “No Code” Delusion
• Images Created from Prime Numbers