To me it will always be a noun. It's a little questionable as a verb. I especially hate the past tense form of the verb, probably because it makes the word sound bulky and awkward: "He impacted my car."
Any of you heard the word "podium" as a verb? This one drives me buggy: "I will podium at the Olympics" or even worse, the past tense: "I podiumed." Doesn't it sound a little dirty?