This is a modern method of scrying and is becoming more popular. Most people are familiar with the sound of when a shell is placed over the ear.
It sort of sounds like the ocean. But in fact it is the sounds of blood flowing through the vessels in your ear.
If however you listen to this sound you will eventually by able to pick up fragments of conversation. At first you may be able to only make out a few words, but in time you will come to understand whole segments of conversations.
The subject of this talk will be usually meaningless, but if you can mentally break into this communication you may find the voices may choose to respond.