Symbaloo is a social bookmarking tool that allows you to collect your favorite websites into webmixes. The difference between this tool and many others is Symbaloo uses a visual interface. Websites are represented by visual tiles.
Teachers can create webmixes to collect websites for all kinds of areas: math games, YouTube videos, search engines, or any topic. They can then share these webmixes through a weblink or by embedding the webmix into a website.
Here is a quick start guide I created to help you get going with this tool.