C Gretchen Altman is smiling, leaning back casually, a cup of coffee in hand — Hills Bros. Coffee, to be precise. It looks like a casual shot, but if you hit like, leave a comment, and tag a friend, you can get three different cups of coffee, for free. Altman is part of a growing trend of "micro-influencers". She has a small following — around 6,000 on Instagram(社交平台). Her going rate is $300 to $800 to promote something. She does some posts in exchange for free goods, as long as it’s stuff she believes in. As a micro-influencer she has a much closer relationship with her followers than a big social media star. "I’m just living a normal life and people relate to that," she says. "They just feel like I’m a friend of theirs." But it worries consumer rights groups. Several recent studies have found that young audiences are largely unable to understand when something is sponsored content. In some cases, it’s clear. When a big star takes to a social media to advertise Coca-Cola, for example, the assumption is that he or she’s probably getting paid to do so. And the posts are clearly labeled as ads, with the caption "advertisement" or "sponsored content". But what happens when an everyday person with just a couple thousand followers takes to social media to extol(颂扬) the virtues of a product? The motivations are not so clear cut. The problem with these social media posts is that you don’t know whether it’s an ad or not. Altman is diligent about using those hashtags(标签). She loves what she does and sees it as a business, but she doesn’t necessarily want to be a social media celebrity. "With social media being so integrated into our everyday lives, we have this unique opportunity that I don’t think anyone has ever had before where we can each be our own brand," Altman says.