With this tool, you can take a portion of a YouTube video, add your own materials and then use for teaching. [So those of you working in schools with YouTube blocked, this is a great work around.]
This is a tile-based bookmarking site. Tiles are clustered and one clicks a tile which may hold many bookmarked sites by category. Apparently many schools in California use this site.
Zotero allows students to keep track of where they researched; helpful for reference and research puproses. Works with Firefox and can sync. Looks good. Download the app (free).