Final answer:
Toys "R" Us acquired KB Toys in 2009, reflecting consolidation in the retail industry.
Step-by-step explanation:
In 2009, Toys "R" Us acquired the remaining assets of the 2-letter retailer KB Toys, which is known for its mall-based stores selling toys and games. The question is a part of retail history, illustrating the trends of acquisition and consolidation within the industry. The reference to mail-order houses and marketing, while informative about the transformation of consumer culture and retail in general, does not directly relate to the answer.