Review on RivalScan by Kyle Kriglstein

I like how it can detect different types of files even if there is no extension attached or only an "unknown" filetype. It is not a plug-in for most browsers so it requires download and installation. Also, sometimes it gets confused about what to do when faced with multiple files at once. You have to be certain of what you're looking for, because it will get confused and you'll need to go back and start over. We were trying to see who was using what type of file format for PDFs in order to have more options for conversion.