Good question, which I don't have a "true" answer for.
My feeling is, as very little percentage of pirate finally bought the app after "trying it", having them downloading the app for free did not help on the sales after. Almost none of those hackers did post on blogs, Twitter, etc so it doesn't help neither.
What might have helped a bit is being listed on appulous, I guess some people are tracking the 'hacker' websites to see what's hot, and what was released recently. What might happen is people buying the app straight without going through the hacker stage. However, as I had 99.3% of hackers on the next days after it was published on appulous, which only 1% bought the app after, I would say it did not impact on my real sales.
I think Photoshop is a different case which you can't compare with mine. I agree with what you say about it, but I don't think it applies on mine (sadly ;).