SlidePresenter is an online presentation service. It has a free account that is full-featured and the service allows you to create videos that are synced with PowerPoint presentations. It is similar to Knovio.
SlidePresenter can be used to create presentations for use by educators in the classroom that can then be reviewed by students at a later date for review or reinforcement or to create training sessions that people can view on their own time. Students can also use it for class projects.
The free account limits videos to 15 min (similar to most of these services) but that is a good way to make sure your presentation is focused and concise. Each presentation can be tagged, embedded in other sites, and easily shared via social media.
The videos are on the left panel and the slides are on the right side.
Sharing and embedding features are on bottom left and tags are on bottom right.
(It is a German company so some times the web page translations are a little awkward, but the product works great).
On a side note, they also allow you, in the paid accounts, to post your presentation and monetize it - charge people access for it. This might be an option for small businesses and education consultants to use for hosting fee-based courses.
Knovio - turn PowerPoint presentation into multimedia video
Google Docs - free, online, collaborative presentations
Present me - easy way to record and share presentations
Desmos - create media rich educational content online
PhotoPeach - easily create and share photo slideshows
Prezi - the zooming presentation editor