Ubuntu's backup thing (duplicity?) does something like this too. I can right-click in a directory and restore deleted files, or on a file and view previous versions.

One suggestion for the author of that webpage, and a common complaint I have with open source software websites in general: tell us what your software does. I haven't used a mac, I don't know what features time machine has in any sort of detail so telling me it's a clone is pretty useless. Give a one-or-two sentence saying what it does, and then some bullet points of key features.

There's more description of the name than there is of the functionality.