Email addresses are used for three purposes:
1) Allowing you to recover your password if you forgot it.
2) Sending updates to *only* those who request them.
3) If you use the forum while logged in, you will get email updates whens someone replies to one of your messages.
We use powerful machine learning algorithms to analyze the data you contribute. These algorithms work better if we know which responses belong to the same person. They work even better if we know a little bit about you (age, language background, and education). You can learn more about how we analyze data in the forum or on the blog.