I first used Voice Thread as part of an online course I was taking. It was available to us to use for replying to discussion posts. Instead of typing a 250-300 word response, we could use Voice Thread and record our response. I was glad for the ability to re-record as I sometimes flubbed words. I found have written, bullet type talking points helpful before I began recording. I think faculty will find this tool useful for many things including audio comments to students about their work in general or their work on a specific assignment. It is good for recording class announcements as well.
https://voicethread.com/