PresentationTube's Chrome extension will let you record while talking over your PowerPoint slides or a PDF. You can record with your webcam turned on or you can choose to just record your voice talking over your slides or PDF. While you're recording you can draw on the screen, add text notes to the screen, and highlight text on the screen.
When you have finished recording a presentation with PresentationTube's Chrome extension you can upload it directly to the PresentationTube website where you can then publish it publicly or keep it unlisted. Much like Google Docs, if you make your PresentationTube unlisted then only people who have the direct link to it can view it.
Applications for EducationPresentationTube's Chrome extension could be a good one for anyone who is looking for a new, easier way to create video lessons based on their existing slides. Unfortunately, it only works with PowerPoint or PDFs at this time. Hopefully, in the future there will be support for Google Slides. In the meantime you can always download your Google Slides as PPT or PDF to use with PresentationTube.