I disagree that any specific advice will help an individual marketer...I think the biggest issue is that the economics of acquisition on social (factoring in internet marketing budgets and customer LTV) doesn't work well for brands that aren't already operating at significant scale. Otherwise, Teespring would be a billion dollar company by now ;)
My guess is that social marketing works ok for brands that have a strong competitive position AND healthy margins.
My guess is that social marketing works ok for brands that have a strong competitive position AND healthy margins.