I wouldn't call instant messaging "social media". I see a fundamental differences between the 1:1 (or 1:n where n isn't that high) bidirectional communications

I wouldn't call instant messaging "social media". I see a fundamental differences between the 1:1 (or 1:n where n isn't that high) bidirectional communications and the 1:world fundamentally one-way principle of Twitter and the likes. Yes I know it happens you get replies but I'd say that's less expected (and less happening). So while you use the one for exchanging infos, you use the other for... advertising? And the latter is less important.