Why is the link of the main page not parsed by social networks and instant messengers?

Question

Parsing

Is there a link why when I insert it into a post for social networks, for example, some obscure data is pulled up?
And for example, when I insert a link into the messenger, it is pulled up as just a link, without a title, picture and description

Answer 1

this article should help, it says about sharing in VK and other social networks. There is also about the OpenGraph protocol, which is responsible for this.