Former President Barack Obama placed blame on tech companies for failing to address the disinformation problem he said the industry has amplified during a speech Thursday at Stanford University. The new information ecosystem, fueled by the rise of dominant social media platforms, is “turbocharging some of humanity’s worst impulses,” he said in the roughly hour-long speech. “But not all problems we’re seeing now are an inevitable byproduct of this new technology. They’re also the result of very specific choices, made by the companies that have come to dominate the internet generally, and social media platforms in particular. Decisions that intentionally...