As part of Google Drive, Google Presentations gives you the ability to put together a presentation, import an already created powerpoint, collaborate on creating a presentation, and offer feedback. You can comment on a shape or an entire slide to give context to your discussion or send an email notification by adding someone to a comment. They have a variety of templates, and you can access your presentation offline as well as when you're logged in.
Prezi is an effective presentation software choice when the ability to pan and zoom in and out emphasizes the particular kind of information or data being presenting.
You can create an Empressr in minutes. And you don't even need to have experience with Flash in order to use it. Empressr’s intuitive features and tool tips help you select the text, images and multimedia (video and audio) assets you wish to use. You can quickly import images from Flickr, Google, Yahoo and Photobucket. You can use your built-in webcam to capture images directly into your Empressr media library, shoot a still, or record video and audio such as voice overs or sound tracks.