Have you ever picked up your phone to answer a call from an unknown number, only to have no one answer?
Your answer to the call could be giving a command to a machine. When you answer a call from a stranger and don't hear anything for three seconds, you're actually waiting for an answering machine to transfer you to a salesperson. 
But that's not all...
Yes, there is a method behind this madness. Knowing that someone answered the call is a confirmation that the phone number belongs to a real person and is active. This shows spammers that there is a victim and the number is available for future scams.
Missed calls are rarely random. In many cases, they are identification calls. Spammers try to automatically verify a number before investing human effort in a target.
What do they do with your number next?
Verified communication data has value, is bought, sold and reused. A silent call can serve as a filtering mechanism, separating non-working numbers from active phone numbers.
In some cases, your verified number may lead to phishing calls or emails. In other cases, you may be the target of a more serious type of attack.
A verified number can be associated with a compromised email address, used for password resets, or targeted for fraud. YES swap.
What about calls that someone answers but after a short delay?
The pause is usually a sample of a specific infrastructure.
It shows systems that handle a high volume of calls at the same time and use algorithms to detect when a human answers. Once a voice is detected, the system routes the call to an active operator. The delay shows the transmission process.
From an operational perspective, this model allows spammers to maximize efficiency while minimizing labor costs.
Although the press releases will range from very select to rare, I said I'd pass...because sometimes the editors hide.
