 eMarketer, however, isn't buying it. It expects sales growth at Amazon will slow from last year's Prime Day. The rise of social media influencers may be influencing a rise in something else, addictive shopping and hoarding. A clinical psychologist tells the Wall Street Journal she's seen an increase in so-called stealth shopping, where people buy things they feel they have to sneak into the house so their spouses or significant others won't notice.