From auctions to buy-it-now on eBay

eBay has changed since I started studying in the late 1990's, when it was all auctions all the time.
Here's the story:

SALES MECHANISMS IN ONLINE MARKETS:
WHAT HAPPENED TO INTERNET AUCTIONS?
by Liran Einav
Chiara Farronato
Jonathan D. Levin
Neel Sundaresan
Working Paper 19021
http://www.nber.org/papers/w19021


ABSTRACT
Consumer auctions were very popular in the early days of internet commerce, but today online sellers mostly use posted prices. Data from eBay shows that compositional shifts in the items being sold, or the sellers offering these items, cannot account for this evolution. Instead, the returns to sellers using auctions have diminished. We develop a model to distinguish two hypotheses: a shift in buyer demand away from auctions, and general narrowing of seller margins that favors posted prices. Our estimates suggest that the former is more important. We also provide evidence on where auctions still are used, and on why some sellers may continue to use both auctions and posted prices.