These things became shit around 2009. Or immediately after becoming sufficiently popular to press out LiveJournal and other such (the original Web 2.0, or maybe Web 1.9 one should call them) platforms.
What does this have to do with search engines - well, when they existed alongside web directories and other alternative, more social and manual ways of finding information, you'd just go to that if search engines would become too direct in promotion and hiding what they don't want you to see. You'd be able to compare one to another and feel that Google works bad in this case. You wouldn't be influenced in the end result.
Now when what Google gives you became the criterion for what you're supposed to associate with such a request, and same for social media, then it was decided.