The online dress stores sector, an integral part of the extensive e-commerce industry, has been under scrutiny in recent times, given its rapid growth and the transformative impact it has on the fashion industry as a whole. This analysis aims to provide an exposition of the key findings and insights that delineate the present and future trajectory of the online dress stores industry.

The first point of deliberation is the staggering market share the online dress stores have garnered over the past decade. The shift from brick-and-mortar to digital has been accelerated by the increasing propensity of consumers to shop online, facilitated by the ubiquity of smartphones and reliable internet connectivity. This phenomenon is aptly observed in the Pareto Principle or the "80/20 rule", wherein 20% of the online stores are believed to account for approximately 80% of the sales. This asymmetrical distribution delineates the dominance of few major players in the market, and their substantial role in shaping the industry's future.

The penetration of online dress stores can be quantitatively assessed through the lens of the Compound Annual Growth Rate (CAGR). The average CAGR for this sector has been an impressive 20.4% over the past five years (2016-2021), indicating a substantial expansion of the online retail space. The sheer magnitude of this growth can be attributed to supply-side factors such as technological advancements, investment in digital marketing, and the incorporation of user-friendly interfaces for a seamless shopping experience. Furthermore, demand-side factors like changing consumer preferences towards online shopping, and the perceived convenience and variety it offers have also boosted the industry's growth.

Geographically, the penetration of online dress stores varies widely. Developed regions, such as North America and Western Europe, are characterized by a high internet penetration rate, advanced digital infrastructure, and high consumer purchasing power, making them the epicenters of online retail. However, emerging economies in Asia and Africa are witnessing a swift expansion of online dress stores, driven by growing internet penetration and rising middle-class income.

While the market share and geographical penetration provide a snapshot of the present, assessing the future of the industry necessitates an understanding of the evolving trends and strategies employed by online dress stores. The rise of data analytics and artificial intelligence (AI) in e-commerce offers profound implications for online dress stores. With predictive analytics, online retailers can forecast purchase behavior, optimize inventory, and enhance the overall shopping experience. AI, on the other hand, offers unique opportunities for personalization. By analyzing user data, AI can generate personalized recommendations, enhancing customer engagement and encouraging purchase.

The sustainability of online dress stores is another critical factor shaping the industry's future. The growing awareness and concern over environmental issues have given rise to "sustainable fashion". Online dress stores are gradually embracing sustainable practices, ranging from eco-friendly packaging to selling pre-loved dresses, to cater to the increasing demand for sustainable fashion.

The online dress stores industry, hence, appears to be on a growth trajectory driven by both technological advancements and evolving consumer behavior. The key to thriving in this space lies in understanding and adapting to these shifts. As the industry navigates through the digital revolution and sustainability challenges, it is poised for a future that is both digital and green, a future that is truly fashionable.