How I Use It
I asked my third graders to independently explore the site. They were not able to do so effectively - they were looking for games and activities and so found it "boring." Next time I will use a projector to introduce the whole class to it at once. That way I can explain what the site is most useful for (i.e. getting project/activity ideas on a variety of topics, not games).
The site is a bit confusing at first since there is not a clear "start here" section, but once I explored around a bit and created a login I got the hang of it. It seems like a good source of ideas for teachers looking for projects/demos OR for parents/families who are engaged and like to continue learning outside of school. Students would like to see their DIY creations online but will likely need significant help making that happen.
FYI - when you are looking for topics many are not typical - e.g. "Cardboarder" has a wide selection of DIY projects that involve making a "prototype" of cardboard.