Instead of using the bloated OAuth multiple requests back and forth, permission keys, auth keys, consumer secrects, etc, etc. you can simply add an additional header saying "client id" which the service provider can then use to "secure" his er her service as he sees fit.
OAuth is a bloated attempt to paper around the simple solution so that the astronaut architects who made it can feel smug about themselves.
OAuth solves no problems, helps nobody and has (drastically) polluted our ecosystem. To hell with that shit.