Listango is an easy-to-use tool that lets you bookmark webpages in public or private lists. Even though it prompts you to add a bookmarklet to your browser, you can also manually copy and paste web addresses.
There are, of course, many of these types of sites, and the best ones are on The Best Social Bookmarking Applications For English Language Learners & Other Students list (I only include ones that allow you to add saved bookmarks manually since it’s problematic to add a bookmarklet to a student computer in school) . The question is which ones are not blocked by school content filters….
Sites like these are particularly useful to my Theory of Knowledge students who have to write a major essay during their second semester.