If you have your heart set on forcing users to register before using your service, then allowing them to verify their identity using Facebook may limit the number of people who drop out.
Potential for sharing
The thought of having all your customers sharing your brand with their friends is probably the main selling point of Facebook Connect.
I’m dubious over whether that actually happens en masse, as I’ve logged into several sites using Facebook and have never shared details of any of them with friends, but there is presumably a proportion of customers who will happily provide their favourite ecommerce sites with some free advertising by sharing purchases.
Access to profile data
If a user is logged in using Facebook Connect the site owner can potentially access profile data and personalise product suggestions based on their social graph.
This can be useful for upselling gift suggestions or for birthday reminders.
Accuracy of data
Often people will use false information or a nickname when signing up for Facebook, and those with really old accounts (like mine) might not use the email address they signed up with anymore.
Users also control their own privacy settings for date of birth, gender, etc. and can restrict who accesses that information.
Loss of control
With more than 1bn users it’s unlikely that Facebook is going to disappear anytime soon, but what happens if it suffers a catastrophic problem with its servers (admittedly that could happen with any third-party service) or simply decides to change its terms of service?
Or, what if your customer decides they no longer want to use Facebook and cancels their account. Probably without even realising it they’ve also cancelled their account with you.
Giving a third-party control over such an important part of your ecommerce strategy could prove to be risky in the long-term.
Some users don’t want everything to be connected
Facebook is a great service and is useful for keeping in contact with friends, but that doesn’t mean I want everything I do online to be shared and connected via Facebook.
Shopping and socialising are too very separate things, so forcing people to login using Facebook is likely to put off a number of users (just ask @lakey).
The sharing options that are often an unavoidable part of a Facebook login means that sites using the system also give off the unfortunate impression that they are surreptitiously trying to force users to act as brand advocates and unwilling advertisers.
Some people don’t use Facebook
Admittedly with 1bn Facebook users around the world you’ve still got a pretty big audience, but believe it or not there are still people who don’t have a Facebook account.
And are you willing to completely ignore these people by relying solely on a Facebook login?
It doesn’t really simplify anything
Other than the username and password, the customer will still need to input most of the other data, such as billing and payment information.
So the argument that it makes registration more convenient for users doesn’t really stack up.
Muddying your brand image
Admittedly this isn’t an ecommerce example, but in this excellent case study from MailChimp Aarron Walter states that the company implemented social logins as a way of reducing the amount of failed login attempts.
However MailChimp found that not only did social logins have limited take up (just 3.4% of visitors) but it also had a negative impact on the look and feel of the site. So much so, that CEO Ben Chestnut demanded that they be removed.
The main concern was that you are placing another brand’s logo on one of the most visited pages on your site.
As Aarron points out:
Call us control freaks, but we built this brand and we ‘feel strongly’ about shaping its direction ourselves. One logo on our login page is enough.
And what if Facebook or Twitter does something awful and suffers a major consumer backlash? You’re putting yourself in a position to feel some of that negative sentiment every time a user sees the logo on your login page.
Remembering your username and password for an ecommerce site you use infrequently is difficult enough, so adding social logins can just cause more confusion.
Instead of just asking the user to remember their logins details, you’re requiring them to remember which of three login options they used in the first place.
This has the potential for causing additional headaches by slowing down the login process, which isn’t great for the user experience.