Telemarketers are annoying. Even if there is a Do Not Call list, telemarketers cannot be stopped; especially, when they are coming India as your phone may show the number as Private or a bogus one.
Ringless voicemail is the newest technology that telemarketers can leave you a voicemail without the phone ever ringing. Imagine you receive 10 voice mails, you have no idea which ones are really from your friends or co-workers without going through every single one of them.
A provider of the service has already filed a petition with the FCC to officially allow it. Should FCC allow it, our nightmare shall begin.