A date is a job interview that lasts all night. The only difference between a date and a job interview is that there are not many job interviews where there's a chance you'll end up naked at the end of it.
Jerry Seinfeld
Replying to all resumes would be the polite thing to do, but often it simply isn't practical. If a company receives 200 responses for an ad, or experiences a continual deluge of unsolicited resumes, it would spend an inordinate amount of time sending acknowledgments. If you really want a receipt for your resume, send a stamped, self-addressed postcard asking for one. If you make it easy, the human resources department will comply.
People and companies like to see their names in print, especially if it took some effort to find them. Chapters 2 and 5 include tips to help you find the real addressee even when the person is trying to be incognito.