I too had not heard of half of these sites. My husband is a IT guy so my kids are really into computers (6-11y) so I try to keep them on fun sites they can benefit from. I thought I would share a few more.
My personal favorite is www.Zoodles.com (parent controlled,progress/activity reports,free super save video emails for kids but only parent approved family & friends that are set up in the parent account can send/receive the emails. Parents & the approved Adults you add can make videos of themselves reading stories to the kids via a window in the "books" that the child can click on and even "turn pages" and follow along. MUST SEE! The basic site is free but the enhanced version is paid. Android App as well!
I hope these sites are usefull