Straight from FASB's Norwalk Connecticut Headquarters:
The Financial Accounting Standards Board (FASB) and the International Accounting Standards Board (IASB) approved a revised definition of what constitutes an asset on October 22, 2007, the first day of their two-day joint meeting.
Following a discussion as to how to replace the word “control” that had been used to link an entity and an economic resource in the prior definition of asset, the Boards agreed to define an asset as a present economic resource, which, through an enforceable right or other means, an entity has access or can limit the access of others.
This revision replaced the word "control" that had been used to link an entity and an economic resource in the prior definition of an asset.