The internet is a network that was originally designed for sending text messages between computers. Text messages need only 7-bits of data, so many internet gateways are 7-bits wide by default. Most non-text files that we use are 8-bits wide. If 8-bit wide files are sent through the internet, they can lose 1/8th of their content and be rendered unusable. It's a bit like sending a big truck through a small tunnel. There are ways to perform a 'binary' transfer via the internet which forces the file to be sent through an 8-bit wide gateway (a bigger tunnel), but the most common way to get around this "bit-width" problem is to encode the 8-bit wide file into a 7-bit wide format (actually a text format). This process will actually make the file bigger in file-length. ENCODING IS NOT COMPRESSION! For Mac users, BinHex is the standard 7-bit encoded format because it preserves that Mac resource fork, as well as the data fork. BinHex files usually have a '.hqx' suffix.