This is a good web tool that allows you to create a personal startpage with your most important bookmarks and RSS feeds.Easy to use, reliable and completely (ad) free.
WikiTube is a cool Chrome extension that adds YouTuve videos to Wikipedia entries. When installed, you will be able to watch videos related to Wikipedia items you are reading.
Twiducate is the perfect solution for elementary and secondary students. Rather than having your students sign up and enter an email address, you sign up and create a class code.Using this code, your students log in to your class network.Here, they can answer questions, collaborate on problems, and even embed pictures and videos. As a teacher you have full control over the network. You can even add other teachers!