Slideshare is a presentation- and document-sharing platform. It is a repository of presentations that can be viewed online or uploaded as PowerPoint, Microsoft Word, OpenOffice, or PDF files, which can be shared either privately or publicly. It is similar to YouTube, but with slide presentations rather than video content. With a free account, teachers can upload files no larger than 100MB.
Teachers can use Slideshare to upload lesson presentations for target language input and for students to practice in the interpretive mode. Students can use it as a tool to produce a product in the presentational mode.
Slideshare - Getting Started (video)
Slideshare can be used for interpretive and presentational communication.