Everybody knows enough about some topic — be it English, science, yoga or bourbon — to teach other people about it. And every topic is covered by content scattered around the Web. The idea behind a new site called Learnist is to give everybody a spot to teach through curation. The site, which is also available as an app for iPhone and iPad, features user-created lessons that bring together Web pages, videos, Google Books e-books and other items on a specific topic. At the moment, only a relatively small group of people approved by the site — including some teachers — can create these “learnings,” but anyone can check them out.