host interactive flash or html5 files for things like virtual tours
Many photographers create virtual tours and walkthroughs for businesses, real estate, and points of interest. While flash movies can be hosted, actual flash and html5 files with interactive content cannot be hosted.
There may be easy checks for the security issues. You obviously do not want the flash file to go offsite... run it in a sandbox so that it can only jump to files in the same directory hierarchy. You might be able to check the swf for disallowed commands, or even recompile it.
But basically, this would be another example that smugmug is dedicated to the needs of photographers.