This excerpt taken from the ATVI 10-Q filed Nov 10, 2008.
Amortizable Intangible Assets
Intangible assets subject to amortization are carried at cost less accumulated amortization. Amortizable intangible assets consist of internally developed franchises, acquired developed software, acquired game engines, favorable leases and
distribution agreements, and other intangibles related primarily to licensing activities and retail customer relationships. Intangible assets subject to amortization are amortized over the estimated useful life in proportion to the pattern in which the economic benefits are consumed, which for some intangibles assets are approximated by using the straight-line method. Long-lived assets including amortizable intangible assets are reviewed for impairment in accordance with Statement of Financial Accounting Standards No. 144, Accounting for the Impairment or Disposal of Long-lived Assets (SFAS No. 144) whenever events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. Determination of recoverability is based on an estimate of undiscounted future cash flows resulting from the use of the asset and its eventual disposition. Measurement of any impairment loss for long-lived assets and amortizable intangible assets is based on the amount by which the carrying value exceeds the fair value of the asset.