I recently clicked through an offer to get a free Back to the Future game episode from Telltale Games. It’s a promotion designed to hook you in to purchasing the full series of games when they’re released. The site prompted me for my login, which I had created the last time they did one of these free episode deals, but this time something was different.

They wanted to know where I lived:

Why do you need my address? What's my motivation to give it to you?

When I first signed up, they didn’t require this infomation. My account existed, yet the only details it had when I logged in this time were my name and e-mail address. That’s all they had required previously, and rightfully so. I had signed up for a free download, and they needed to notify me about my “purchase.”

On the surface, it makes sense. A fair trade of software value for valuable personal details, right?

Certainly, some customers will buy into this. They’ll pony up their mailing address and other contact details for a freebie with perceived value of $5 or more. But others will question why they need this information. They’re not sending a physical CD in the mail with the game on it. They’ll send me an e-mail notification when it’s time to download it. What are they going to do with the address? Direct marketing? Sell my information to a third-party? Either way, I don’t want it.

So some people – maybe the majority – will submit a fake address. 1234 Noneofyourdamnbusiness Lane, 1600 Pennsylvania Ave., or perhaps a choice expletive or two.

And now you have a problem: data integrity. A significant part of your database has bad data in it. Supposing you did have a use for the mailing address that most customers would love – say, you decide to reward them with a free disc-based game or promotional (yet adorable) sticker set that everyone would love to find delivered to them free of charge via postal mail – you’d have to do a lot of scrubbing to only send to the addresses that appear to be valid. And, even then, expect a lot of returned mail!

There’s really no good reason to ask for a mailing address unless you need it right here and right now to fulfill a customer’s order.

To be fair, Telltale does sell t-shirts, posters and shotglasses – but I wasn’t ordering those. If I had, then the transaction flow should be modified to require my shipping address. And if I was buying something – even a downloadable game – with my credit card, I’d expect to be hit up for my billing address to validate my identity and complete the transaction. In those cases, the customer will supply these details readily and, most of the time, accurately because they understand the need for it and want to receive the product they ordered.

Any time you ask for information that’s NOT needed to fulfil a transaction, you’re asking for trouble. It may be a little extra work to build that logic into your shopping cart, but it’s worth it – both for the customer’s peace of mind about your company and the quality of the data you collect.