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.
I am a big fan of diigo (social bookmarking), which is not typically used in schools and I think it should be used much more. Here's a sensible approach to using with students.
KeepVid (free) allows you to download videos from many places (including YouTube, Flickr, TED, Vimeo and more) and then show in your classroom. It's free--you choose whether mac, PC, mobile, etc and the download. It really addresses where some schools 'block' all YouTube or there are buffering issues. I tend to use the mp4 version, but you have choices of file type too.
It's an iPad program for teachers and students. If a school has a iPad cart, the iPads are distributed to a class of students and then the teacher uses his/her iPad to push PPt's, movies, documents to the students individual iPads. It's very interactive and the teacher can wait for students to respond on their iPads (questions, drawings, quizzes, etc.) before going forward with the lesson. The teacher obtains a roster of students participating and see how each is doing with the lesson tasks.
Apps for chromebooks; due to their low cost, chromebooks are becoming more widely used in schools. Here are Apps and resources that work well with chromebook
Nanoogo--This FREE site encourages children to be creative and share ideas. It's a cross between a blog and a digital canvas and formatting is really simple. Users just drag and drop the images and text however they wish. There is also a teacher sign up option, which lets you quickly add a whole class or school. Worth a look.
National Education Technology Plan. Technology Curriculum--infuse tech with major changes. Good reading...my sense is that we, as educators, need to be more proactive about leading with technology.