Our LMS had a built-in functionality for users to submit links and tag them, but other options include setting up a class Diigo account with one class username and password. If the majority of participants are already on Facebook and Twitter, other options include creating a dedicated course Facebook group to share content, or setting up a class hashtag (ex. #AU1234) for Twitter to categorize and easily reference all class tweets. (Read further ProfHacker reflections on teaching with social media.)