Social wasn't always sole powered, only began with the later social networks, not the early. And now people are retreating to smaller communities anyways.
Testing on IE6 wasn't the requirement, all browser's was. IE shipped default on windows and basically forced themselves into the browser conversation with an incomplete browser.
I don't mean social as in social network. I mean that people have always been a key aspect of the technology and how it it practically works.
Yes, yes, IE6 shipped by default shipped by default on Windows. And therefore if you wanted a website that worked, you tested against IE6. Otherwise people would try and use your website and it wouldn't work and they wouldn't blame the browser, they would blame your website.
Those social aspects introduce a bunch of not necessarily written rules that you just have to know and learn as you develop for the web.