Download of Youpp 0.0.3 for Mac was on the developer's website when we last checked. We cannot confirm if there is a free download of this app available.
According to the results of the Google Safe Browsing check, the developer's site is safe. Despite this, we recommend checking the downloaded files with any free antivirus software. The application lies within Audio & Video Tools, more precisely Streaming Media. This free software for Mac OS X is an intellectual property of Ambrose Chua.
From the developer:
Youpp is a free open source Youtube client for Mac computers. This tool is built to watch YouTube videos as a floating window, allowing you to use other applications while watching. This program has an intuitive interface and can be easily modified without setting up an IDE.
You may want to check out more software for Mac, such as Oplayera, Machinima Respawn or Jenny FM, which might be related to Youpp.