It's great how you do these articles, provides some general A/B testing info while also promoting your product. Only negative would be the ones I've seen voted up on hacker news all contain many variations per test, would be good to also see those where you can see the direct results of a single change, although you may have done these to.
Is it hard to get users to open up and talk about their product use in this detail?
Yes, it is VERY hard to get users to talk about their conversion rate, traffic and strategy to increase sales. Majority of them consider this information as critical to their business and don't want their competitors to know what they have been upto.
Is it hard to get users to open up and talk about their product use in this detail?