The popup should have the ability to "bookmark" the current page for the class. On demand a new bookmark folder, named after the group, would be added to the bookmark toolbar for all students, and all bookmarks would go in there.

There wouldn't be any sync, students can delete bookmarks, and they can't be updated, just added.

A teacher should be able to send a message to all students. It will simply create a popup notification.

You can screenshare so everyone can see the same things, but that's one way communication and doesn't let the students participate. Students can't interact, you can't show them tools they can use at that moment, you can't add new ways to pair students up, etc.

We should do better! And it should work regardless of what tools you are using – not just Google Docs, or some other educational tool. Everyone is using multiple tools now.

Sometimes the teacher will want to setup a one-off task for students. The current page can be "launched" for all students, with a note on purpose. This opens a new tab (that will be a normalish tab with no updating). The note will be left in a popup inside the page, and should persist indefinitely.