Messenger Facebook and Vkontakte what is the connection?

Question

Messengers

Hello connoisseurs!
Can you tell me why this is happening, what are the reasons?
A person with an Iphone enters Messenger Facebook and at that time "online" Vkontakte starts to appear? At the same time, Vkontakte is "online" only while entering the Facebook Messenger, and not all the time you are there. (let's say a person logged into Messenger at 12:00, at the same time Vkontakte is displayed online, he sits in Messenger until 12:10, and Vkontakte shows "logged in 10 minutes ago").
What could it be? What is the connection between them? Some kind of plugin? Or sync accounts?
I beg you to help me figure it out, friends. This is very important to me. thank you!

Answer 1

Here is a good site for finding all the information on a person VKONTAKTE - https://vkontaktepoisk.ru/