Shares of eBay (Nasdaq: EBAY) opened lower this morning, after the head of its marketplace division announced that she would be stepping down. Lorrie Norrington is leaving for "personal family reasons" after spending just two years at the helm.

eBay's marketplace subsidiary watches over the namesake auction site, the StubHub ticket exchange, and the company's many global online classifieds endeavors. Despite making inroads into mobile commerce and perpetually tweaking its seller terms in order to appease disgruntled power sellers, this isn't really the division that's been driving eBay these days.

PayPal is the best reason to grab a piece of eBay these days, growing faster than

A replacement wasn't named in yesterday's press release, and the gig is going to be a challenge for whoever steps up.

In the past, eBay has covered for its marketplace shortcomings through acquisitions. Whether it was StubHub or South Korea's Gmarket, eBay has already bought up most of the beefy targets short of Latin American speedster MercadoLibre (Nasdaq: MELI). It could also make a play for crafts marketplace Etsy before it goes public.

The Internet was the perfect catapulting vehicle for eBay in the 1990s, but now it's also a threat. Charging folks for online auctions isn't easy in this era of Craigslist, Facebook, and countless other outlets for free listings.

It would make sense for eBay to move closer to more conventional e-tail. It will never be (Nasdaq: AMZN), but it wouldn't be a shock to find eBay snapping up (Nasdaq: OSTK) next year. It could pair that up with a purchase of B2B surplus marketplace Liquidity Services (Nasdaq: LQDT) to create immediate diversification away from consumer auctions.

The one thing that eBay can't do is stand still. The market is evolving quickly, and eBay has a vacancy that needs to be filled just as fast.

What would you do if you were the new head of eBay's marketplace division? Share your thoughts in the comments box below.

MercadoLibre is a Motley Fool Rule Breakers pick., eBay, and Liquidity Services are Motley Fool Stock Advisor recommendations. Motley Fool Options has recommended a bull call spread position on eBay. Try any of our Foolish newsletter services free for 30 days. True to its name, The Motley Fool is made up of a motley assortment of writers and analysts, each with a unique perspective; sometimes we agree, sometimes we disagree, but we all believe in the power of learning from each other through our Foolish community.

Longtime Fool contributor Rick Munarriz is a satisfied eBay user with 178 positive feedbacks to show for it. He does not own shares in any of the companies in this story. He is also a member of the Rule Breakers analytical team, seeking out the next great growth stock early in its defiance. The Fool has a disclosure policy.