Can YouTube videos be viewed without using the Adobe Flash Player plugin? If so, what other specific software is necessary?
Sure! You can use the HTML5 version of YouTube.
All you need is a web browser that supports both the video tag in HTML5 and either the h.264 video codec or the WebM format (with VP8 codec). These include:
- Firefox (WebM enabled version available here)
- Google Chrome (h.264 supported now, WebM enabled version available via Early Release Channel)
- Opera (WebM enabled version available here)
- Apple Safari (h.264, version 4+)
- Microsoft Internet Explorer with Google Chrome Frame installed (Get Google Chrome Frame)
Youtube also has videos available using the HTML5 video tag. This is currently only supported in recent browsers though, and there are some additional pitfalls in the user experience from not using flash which are outlined in this post on the YouTube API Blog.
If you use a Unix system, this should be useful.