Next to sequencing and scoring on the computer, the most common MIDI application performed is the storage and retrieval, and exchange of MIDI data. Editors and librarian utilities make this process quick and easy. Not much, I bet.
People often forget that their computers make terrific databases and storage units.
Just as you would save the addresses and phone numbers of your clients in a database, you can store information on your MIDI equipment on your computer. Generally, it would be System Exclusive messages. I say this because all other types of messages are not of particular interest to any one machine. System Exclusive messages allow MIDI devices to transmit 'private' information to certain specific devices, but not to others. In fact, the information does get transmitted to all devices, but only those that are supposed to read it actually understand it.