Testing at school with a mac, Hit play video, the your browser is not supported message came up. However, java is installed, so it should have worked.
The applet definitely can work, and I succesfully played http://people.xiph.org/~oggk/elephants_dream/elephantsdream.html in this version of safari (After clicking through many scary applet-not-signed warnings)
Safari Version 6.1.1 (7537.73.11)
Java 7 (u45) (according to http://www.whatismybrowser.com/is-java-installed - can't figure out how to find out plugin versions directly).
The java applet fallback should let us reach a good portion of desktop Safari and IE users, so we should figure this out.
Version: unspecified
Severity: normal