Quote from: sottwell at Sep 17, 2012, 11:55 AMSuppose you're not making a package or anything like that; I just want to specify an external source for static resources. Or does a custom Media Source have to become a full-blown package?
If you are writing a driver to be able to interact with a specific storage service that is not already available as a Media Source type, i.e. filesystem, S3, then you are creating a custom Media Source class. For example, Digital Butter has created a Custom Media Source class for working with file on DropBox.
Whether or not you package it up or provide manual install instructions is up to you, but packages make maintenance easier for those using your extra.