It was originally made by a redditor because reddit's own image hosting was too cumbersome and slow. It was fast and lightweight. Drag an image, get a link to the image, there was nothing else no comments no cats popping up on the screen. Now it's basically its own social platform.
CloudUp is a web-based HTML5 app and website meaning it can be viewed from any modern browser form any device. There's a native desktop Mac and Windows app available and native iPhone and Android apps being worked on.
After dragging & dropping files, a link for sharing will be in your clipboard. You can also paste from your clipboard into the web view. When you share a stream with someone they can start viewing it even before all files have been uploaded. All this makes it easy and straightforward to use.
When uploading videos, photos or audio, CloudUp will transcode a version of the media so that it can be viewed right from within the app without requiring a download.