Virtual Shelf for Mac lies within System Tools, more precisely File Compression.
From the developer:
Are you looking for a way to compress your files to save disk space? Are you looking for true Mac OS X compression and backup software? Everyone around you talks about backup, but you still always forget them ?
With Virtual Shelf , discover a new way to archive and backup your data. Simply create archives, and add items by drag and drop operations.
You may want to check out more software for Mac, such as Shelf Leveler, Music Shelf or Virtual CD RW, which might be related to Virtual Shelf.