If you are not using Slideshare, you should be! It allows you to upload and share any PowerPoint presentation or PDF.
Now you can turn your Slideshares into animated GIFs with GifDeck. It’s easy to then embed that GIF into an email, blog post or tweet.
Here’s an example from a presentation I did on Big Data and PR. It captures a handful of the slides from the presentation, which makes for a much more compelling graphic vs. a single static image.