I learned about this comic creator site from the well-heralded Free Technology 4 Teachers blog. This site is one of many where you can create comics online and then share them (Toon Doo, etc.) However, what sets this site apart from others is the educational section to it.
There are a ton of features that is designed specifically w/ schools in mind such as: private rooms/URL's, teacher to student messaging, a "lesson bank" to share/upload lesson plans, etc etc. Another nice feature is that it will easily interact w/ any CMS. For example, you can set your page to private so nobody can get in w/out a password or you can set individual permissions for students to make sure that nothing inappropriate gets posted up online.
I would think w/ these features in place it would abide by most CIPA/COPPA compliance rules. For more info click here.
Below is a Time-Lapse video of Pixton in Action
Coming soon... Pixton comics now animated... I'll post my example soon after... click here.