I am designing an application where the user has to create an account to purchase a product. A standard thing to do when a user has to register an account (eg a forum) an activation email is sent to confirm the identity.
In a situation where the user has to register an account then purchase a product, when the users intention was to get the product; should an activation email still be used?
I used to specialise in e-commerce sites, and we would never require confirmation of an email to register and buy. The email address was part of contact details, nothing else, and so not critical to the process of buying something.
And as giraff says, lazy registration is the route forward - you should not have to "sign up" for anything just to buy. You should have the option if you buy regularly, and want to monitor your purchases, but that is a separate requirement.
The only time an email address should require to be validated is when the email address is the core information you are gathering - for example, to send electronic versions of products, or for newsletter.
You should, however, send a confirmation email, so that if I were to put in your email address, you would know, and get it cancelled.
But my perspective, as a user, is that the least I need to do to get something from you the better. And waiting for an email may just be the thing that sends me to a competitor.
I would first ask do you need their email to be correct? Is it absolutely vital that their listed email be correct for the transaciton to be complete? You're talking about not only expecting them to fill out a form and register (which I also would recommend strongly against unless necessary), but you're expecting them to trust you with a real email account, open a new tab, load their email, check it, find your email, click your activation link, then continue their transaction. This isn't as simple a step as it sounds on paper.
Don't forget the 300 million dollar button. Extra steps always lose you users, and when you're talking about losing users that already want to buy your product you're doing the most possible harm with every extra step you add by losing users. Consider the typical user of your site; are they people that all have long term relationships (business partners) that will return to your site and will place more orders, or are they users that happened to find your site and want to buy a thing or two and may never buy again? They don't need an account for that, and you certainly don't need their email.
It depends what you use his email adress for. As you probably ask for other contact details as well, email loses its function of "identifier", becoming only a "possibility to contact amongst others" and "simple way to give feedback about delivery status" - so you, as a site owner, do not need the assurance to have a verified email adress (if they fake their post adress, the product won't be delivered anyway).
However, if you want to use the email for newsletters, I would require activation: not for making sure the client is who he claims to be, but rather to make sure that another person feels "spammed" because the client inadvertently misspelled his adress.
But a priori, to buy a product, you don't even need to register - see the lazy registration pattern. Related info would be in "Does logging in turn away visitors?" and other questions on UX.
I would say YES.
User may want to buy only one product and won't return after, so he/she just dont activate an account, but when user activate an account you have opportunity to mailing, so it good according to site owner. I would leave that functionality.
Reading the answers above I think that there is a part of the right answer in each one of them. Nevertheless the right answer for me is the following (excuse me if it is a bit long).
Email is good. Not verifying the typed-in email is ok, but you have at least send notification mail to say it's added. (As the guys mentioned above). But what's the point then to send mail but not add a quick link of verification. User will be spammed with mail, but you won't get any benefit from that. I guess that's a lose-lose situation.
The right thing for me is: Keep a "Is your mail verified?" status. So when user registers, send him/her a verification link, but do not require it verified to continue registration. Complete registration nevertheless if user verified or not but keep him posted that he didn't verified his mail.
Use the first convenient moment (Newsletter subscription form or so) to tell the user: Dude, your mail is not verified yet, and now is the time you have to, else this function won't work.
So this would kind of be win-win situation (as at least I imagine it :) ). You won't stop users registering because of their mails, you will send notifications and you will push users to verify in the future convenient moments. As of percentage of profile completed for example.
I hope that helps you decide.
