[dogma1138]

It wouldn't surprise me if people with active netflix accounts tried to login into that page which is why they changed how it works, also like with any A/B testing it's not always clear what user behaviour they were seeking to change or reinforce, and it's usually more than one.

For example the buy now vs add to cart only on the Amazon one might have been looking at more than just how many products are sold, they might were also been trying to see if they can say reduce impulse buys that result in returns without lowering purchases that do not, in fact the reason they've kept the buy now might be because it actually reduced the return rate as people interacted less with the site and didn't buy additional items that they returned later.