On <a href="http://codecademy.com">Codecademy</a>, you can learn to program in various languages. It starts off very slowly and is targeted at non-technical users. That's their claim anyway---the material in the courses I looked at ramps up pretty quickly. Anyway, the interesting thing I saw was in their introductory test. It struck me as a subtle way to get you to enter your email address. I'd just recently discussed this on a project I'm working on: how can we make it fun for the user to enter personal information? The goal is not to sell that information (not yet anyway, but who knows what the future holds), but to be able to enhance---nay, <i>personalize</i>---the service. Personalizing has a bad reputation but can be very beneficial. For example, if you're using a site for free and you're going to see offers and advertisements anyway, isn't it better to enter a bit of data that will increase the likelihood that offers and ads are interesting? Each person can---and should---decide for the themselves what to make public, but the answer isn't always necessarily <i>no</i>. <h>How Codecademy gets your email</h> <img src="{att_link}first_prompt.png" href="{att_link}first_prompt.png" caption="First prompt" scale="75%"> Here they teach you how to use the "length" method by measuring your email address. Sneaky. I like it. <img src="{att_link}second_prompt.png" href="{att_link}second_prompt.png" caption="Second prompt" scale="75%"> Even if you don't given them an address, they re-prompt you to enter your email, but it doesn't come across as pushy because you're taking a test. I thought that this was pretty subtle. Because of the context, people who would ordinarily be sensitive to giving up their email might not even notice. Why? Because they want to answer the question *correctly*. They don't want the site to judge them for having entered something wrong, so they do as they're told. Is Codecademy collecting emails this way? I have no way to be sure, but they'd be silly not to.