Web 2.0 for Educators

One tool that I've really started using educationally this year is Pinterest. Over the summer I started seeing the value that it has educationally. I absolutely love it. Somebody out there has already found or made a lesson that worked for them and are willing to share it with other teachers. I can do a search for a specific topic and find endless resources of activities and assignments and lessons. Last summer I began by doing a broad search for Common Core 7th grade math. I found people that had shared an entire unit. I firmly believe in the saying "Why reinvent the wheel?" If people are willing to share what they've found and made, then it must be of some value. I've only used this as a tool to use as a teacher, but I'm sure eventually someone will start pinning on how to use Pinterest in your classroom. Ay ideas?