I recently bought some clothes from Boden and noticed this little gem on their sign-up form. Underneath where they have the options to select your date of birth, they have a checkbox which says “Mind your own business, I’ll keep my date of birth to myself”. I thought it was a real nice touch, as there is nothing worse than a company making you disclose sensitive information without a real cause.

If you click on the link in the form which says “Why are you asking me this?” it brings up this little dialogue which explains the benefit of giving this information — We’ll give you birthday offers! — and the ramifications of not doing so — We just need to know you are over 14 for legal reasons.

It would be interesting to see the different conversion rates depending on whether this was included or removed from the form, although I suspect they would be taking into account the benefits of having age data or whether there was an increase in customer spend after they received these offers.
Another thing I was impressed about my Boden experience was their after-sales experience. I emailed to query about a discount and received a well written and detailed email in return, from a real person. Plus, a few weeks after my order arrived, I got a discount voucher in the mail, for my next order. It serves as a gentle reminder and perhaps a push to commit to another order.
The best thing is that all these changes probably came from different departments (marketing and UX) but overall they add up to a great experience for the customer.