On television — including during the NBA finals, in which local heroes the Golden State Warriors would ultimately clinch the title — ads featured footage of brown boxes rolling down a warehouse roller conveyer. This was all the handiwork of eBay, the auction website that rose to fame by promising a treasure trove of used goods that could be delivered to your door, provided you make the winning bid. Then, its age started showing, and eBay decided to make a statement in recent months: We're a fun, exciting shopping destination — they posited in this summer's massive marketing push — not just for old car mufflers and used silver tea sets, but rather high-end accessories and next-generation drones.