One of the first posts I made was about Readability. Readability has been changed and is now called Mercury Reader.
If you had Readability previously installed, it has been updated for you.
Mercury Reader still allows you to remove webpage noise and clutter from an article to make it easier for students to read. It also still allows you to make minor changes to font style, size and light/dark background options.
Mercury Reader does have a few new options available. There is a quick keyboard shortcut (Cmd + Esc for Mac users, Alt + ` for Windows users) which allows you to switch the Reader on and off in any article. There are also updates in the printing and sharing options. You can now share through Facebook, Twitter and Email.