I've seen a number of recommendations to support guest checkouts. eg Should registration be optional on an e-commerce site?

In an e-commerce site where logged-in customers can view previous orders, delivery address, etc, what's the appropriate thing to do when a customer registers with an email that's already been used for a guest checkout?

  • Forget the guest order and treat the registering customer as a completely new customer, because that better respects the customer's privacy; or
  • Associate the previous order(s) and address(es) with the new account, because it saves the customer time;

Similarly, what about a customer trying to do guest checkout with an email that's already associated with an account? Ignore the existing account or alert the customer?

  • 1
    Privacy on the internet? :P
    – bjb568
    Commented May 13, 2014 at 2:49
  • 2
    :) For a while now I've wanted to make a "Forgot Password" link that takes redirects you to the NSA.
    – David
    Commented May 13, 2014 at 3:30
  • 2
    Redirecting? I don't think that's necessary…
    – bjb568
    Commented May 13, 2014 at 3:36

3 Answers 3


The two solutions that you suggest are the extremes on a possible range of solutions. Often the best solution is somewhere in the middle. The fact that you've recognized them doesn't necessarily mean that your two only choices are forgetting and importing.

One option is to say "Hi, we noticed that this email has already been used on this site. You can import your old information and reuse the payment and shipping details". Then you provide the options of View Old Information | Discard Old Information (let them review and revise it before importing). This option does reveal that you haven't respected their privacy, but it does that in a more careful way than just importing the stuff. Of course, you need to make sure that they log in with the original password or let them reset the password. Otherwise people can abuse this and access sensitive information about other people's purchases.

An even more discreet way is to ask "Would you like us to check whether this email has been used on this site in the past?". The twist is that you only display this message to people whose email you've already recognized and not to everyone. If they say yes, you present them with the same options as above. This also reveals the fact that you've retained their data, but it's not as obvious as the other options.

If a customer tries to do guest checkout with a registered email, you should definitely alert them, and if they can't log in, you should also alert the account owner.

  • Retaining the data is not what I find troublesome. I would expect an e-commerce site to retain the details of their orders, including the e-mailaddress I provided them to get in touch with me. What would trouble me is recognition/use without being prompted by a specific action by me. Recognizing my e-mailaddress when I enter it to register on the site would be sort of fine. Doing the same when I enter it for a new "anonymous" order would get my running muscles warmed up. Asking for permission to check IMHO is the best. Commented May 13, 2014 at 9:18
  • Thanks. I wanted to contrast the conceptual options, but I agree there's scope for presentation. The trouble with making "sure that they log in with the original password" is they wouldn't have created a password during a guest checkout. Maybe emailing an account activation link would be the thing to do, so they can see previous orders, but only after we've established they actually own that email address.
    – David
    Commented May 13, 2014 at 11:08
  • +1, In my opinion, giving the customer the freedom of choice on such matter is the best option. Giving the users such agency kind of solves the "Can't please everyone" problem. The discreet option here seems the way to go. Commented May 13, 2014 at 13:48

I've actually done some testing on this.

We changed our check out option to just a form that wouldn't remember the user by default and a login option. When filling out the form and confirming the order, the user would be prompted by a dialog asking them if they would want to register, pointing out all of the advantages of registering.

With that came the ethical question: could we use previous entered information? The information they just entered and any information entered in combination with the same email address.

A small survey gave clear results.
People were okay with the information they just entered being used, so the user only has to come up with a password to create a profile.
But using older information was considered 'a slight breach on privacy' by 54% of the people questioned. This because people expect you to 'forget' their information as soon as they ordered, until something is amiss and they call customer service. In that situation they expect you to know something about them.

  • Thanks. Yes, I was wondering if that would be the perception. It'd help to know, were the other 46% okay with it, or did some of them think it was a significant breach of privacy?
    – David
    Commented May 13, 2014 at 11:10
  • @David They thought it would be convenient Commented May 13, 2014 at 12:01

There has actually been a study conducted on what irritates users the most on an e-commerce website. A recent Econsultancy / Toluna study found that 25.6% of online consumers would abandon a purchase if they were forced to register first. enter image description here

I feel like even the largest e-commerce websites today including amazon do not require users to register before completing their purchase. Allow users to have the choice and if they enjoy your site they will register because they will turn into return customers. Some users may not want their information on sites across the web so they may avoid your site if it forces them to register. Just some information, hope it helps.

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