Crocodoc converts PDFs to HTMLs and allow users to openly make comments, creating open collaboration. Then you can download the improved document and share with colleagues.
Jing makes screencasts easy. Insert a Jing screencast into your collection as an opening overview or before a resource that you want students to pay careful attention to.
Flubaroo makes grading easier. Embed a Google form into your collections for short CFUs or at the end of a segment before they continue to the next resource. Once students have studied the collection and answered your questions, let Flubaroo compile the student performance data and present it in a fast and organized way. Grading will never be the same.