Yes, in this case you could keep using p-values (if you really wanted to...), but with reference to the value of, say, each customer. (This is what I meant by setting the threshold with respect to decision theory.) If the goal is to use on a site making millions of dollars*, 0.01 may be too loose a threshold, but if he's just messing with his personal site to help readers, a p-value like 0.10 may be perfectly acceptable.

* If the results were that important, I think there'd be better approaches than a once-off a/b test. Adaptive multi-armed bandit algorithms sound really cool from what I've read of them.