DocSlide - DocSlide is an online document and knowledge sharing platform.
Mixbook - Mixbook is an online photo design tool and product service that allows customers to design customized photo books, cards, calendars, and photo prints through its online interface.
SlideShare - Discover, Share, and Present presentations and infographics with the world’s largest professional content sharing community.
SlideBoom - Upload and Share PowerPoint presentations with your family, friends, colleagues, clients and the whole world
Scribd - Unlimited books, audiobooks & comics. Unparalleled discovery. Any device. $8.99/month
Bitstrips - Bitstrips is fun and engaging app that lets you create your own comic strips right from your mobile device. It's essentially a social network that allows its users to share self-made comics as opposed to photos, memes, videos, or other posts.