Science paper piracy site Sci-Hub shares lots of retracted papers

Most scientific literature is published in for-profit journals that rely on subscriptions and paywalls to turn a profit. But that trend has been shifting as various governments and funding agencies are requiring that the science they fund be published in open-access journals. The transition is happening gradually, though, and a lot of the historical literature remains locked behind paywalls.

These paywalls can pose a problem for researchers who aren't at well-funded universities, including many in the Global South...