My field is fairly technical, and someone in HR likely knows nothing about any job I'd be qualified for. So it's all down to buzzwords, and a guessing game - which buzzwords might the technical manager have written down and told the HR wonk to look for?
If I've guessed right, I get an interview, or a phone call to get more information. If I've guessed wrong, I get a letter thanking me for wasting both our time, but "we're still exploring our options."