That native of the community of illiteracy - the Oxford English Dictionary - has an entry "impact, v.". Citations of its use as a verb go back to 1601. The last citation is dated 1972. 

>
>Subject: standards
>   From: Tim Thompson <[log in to unmask]>
>   Date: Tue, 04 Apr 2006 22:52:33 -0400
>     To: [log in to unmask]
>
>Yargh! I feel like one of those crusty old curmudgeons, at least one of 
>which shows up on everyone's dissertation committee, but in the interest of 
>students and the impressionable young that might be on this list, I'm 
>compelled to point out:
>
>Amy, "impact" is not a verb. I know the native speaker is always right (Dr. 
>Hardaman beat it into my brain) but we don't have to be natives of the 
>community of illiteracy.
>
>Marcy, the expression is not ". . . fair so well . . ." but " . . . fare so 
>well . . .", as in "wayfaring" or traveling.
>
>Academic and bureaucratic gobbledy gook is bad enough, but can't we maintain 
>some devotion to clear writing?
>
>Tim T.
>pedantic curmudgeon