I don't think there is a standard.
I have to admit, that are times I forgot to send out notice I have filled a position to all people who submitted resumes.
Wow! I really think that unfortunately, you're a minority there. For this summer, I have sent out approximately 30 resumes and heard back from 1 person.
I have to say that I find it very frustrating and discouraging. I email, fax and post my applications and about 14 days after, whenever possible, send an email to follow up, but this time around I got nothing in response.
I recognize that there are certainly different circumstances regarding every job out there, but 30 applications and 1 response really makes me question my own abilities.
I wish more people took just a moment for a simple "We thank you for your interest, but have already filled the position." I know it would make me a little less stressed.
And I honestly don't think it has anything to do with my letter. It's literate, well written and was proofed by the literary manager at the theatre I'm currently at. I've used it numerous times and to be honest, never not gotten a job that I wanted until now.
Frustrating.