Commonlit is an organization that is building sets of thematic discussion questions to use in conjunction with upper elementary school and middle school students.
TL Virtual Cafe is an online community for teacher-librarians to connect and learn from each other. TL Virtual Cafe hosts numerous webinars and online discussions including a monthly show called TL News Night. TL News Night features conversations with experts from state library associations, an overview of "this month in libraries," and a tip, tool, or title of the month.
On Classmill you can create public or private (invitation-only) courses. Courses are built as a series of modules. In each module you can include videos, text, images, links, and file attachments. You can also embed games and interactive simulations into each module. A discussion forum is automatically added to each module in your course. If you make your course private you will have to email invitations to your students.
With Known, students and teachers can easily create websites, share content, and discuss projects. Known for Education gives individuals all the features of Known Pro at a lower price.