Jose Cebrian, an Acxiom executive, said email campaigns drive search. Bumps in search traffic can be tracked to large email campaigns.
Separately, he said “you can decrease engagement” if you send irrelevant and too many emails. The “engagement index goes down the pot.”
Today, email programs, particularly in the retail category, are so frequent, it can be difficult to measure effectiveness and many marketers don't have access to top-notch analytics.