Brands have dramatically improved fulfillment speed: a fifth of brands in the 2019 Index now offer free two-day shipping, and the number of brands offering next-day shipping has doubled. Recognizing that mobile accounts for 55% of online traffic on average in this sector, Index brands have more than tripled investment in mobile Showcase product ads year over year. Additionally, shoppable Instagram content has proliferated, cementing the social platform as an essential channel for product discovery. While fast fashion brands once exemplified the ability to quickly respond to trends, a new class of disruptive upstarts raise the bar for sophisticated, category-specific online experiences.