An update on EmailYourInteriewer.com, which lets job-seekers send an anonymous, polite letter to employers who interviewed them and then never bothered to get back to them: It's now generated 95 letters to employers.
A couple of employers have written back to apologize. Here's one of those replies:
Please let your candidate know that I apologize if this occurred. I conduct second or third interviews around the country and make it the responsibility of the hiring manager to follow up w/ all candidates. I will follow up w/ the managers who currently have opening to ensure they are communicating w/ all applicants.
If you've been frustrated yourself by not hearing back from companies after interviewing, why not politely let them know. Go here, and the work will be done for you. (Just make sure to follow the rules.)