This excerpt taken from the BLKB 10-K filed Mar 2, 2009.
Intangible assets are amortized over their estimated useful lives as follows.
The Company evaluates the recoverability of intangible assets periodically and takes into account events or circumstances that warrant revised estimates of useful lives or that indicate an impairment may exist. A substantial portion of the Companys intangible assets was acquired in business combinations. No impairment of intangible assets resulted in 2008, 2007 and 2006.