This excerpt taken from the VRSN 10-K filed Feb 29, 2008.
Valuation of long-lived assets
Our long-lived assets consist primarily of property and equipment and purchased intangible assets subject to amortization. We review long-lived assets for impairment whenever events or changes in circumstances indicate that we will not be able to recover the assets carrying amount in accordance with SFAS 144. Such events or circumstances include, but are not limited to, a significant decrease in the fair value of the underlying business or asset, a significant decrease in the benefits realized from the acquired business, difficulty and delays in integrating the business or a significant change in the operations of the acquired business or use of an asset.
Recoverability of long-lived assets is measured by comparison of the carrying amount of an asset to estimated undiscounted cash flows expected to be generated by the asset. If the carrying amount of an asset exceeds its estimated future cash flows, an impairment charge is recognized by the amount by which the carrying amount of the asset exceeds its fair value. Any such impairment charge could be significant and could have a material adverse effect on our reported financial statements.