Many E-Commerce sites offer you the ability to register on the site to make it easier to shop online. The site can then remember your address, name, email, and shipping details so you don't need to enter them every time you shop with that website.
Interestingly though, is the number of E-Commerce sites that require you to sign up for an account before you're ever allowed to place an order. How many times have you been on a website and gone to place an order, and the site has asked you to create an account before you're allowed to go through the checkout. Sadly, this is the default state for a number of E-Commerce platforms.
Think about it this way. Imagine you go to a store, you spend time looking at what you want to buy. You grab it and take it to the checkout to buy it. Then the cashier says, "I need a password before you can buy". You say "no, I just want to buy this". The cashier says "I need a password before you can buy". You say, "just sell me this, I'll create an account if I like the product and want to buy more". The cashier says "I need a password before you can buy". The outcome is predictable.
The fact of the matter is, 88% of online adults don't like being asked to register on a website.  And why would they? All they want to do is buy something, they don't want a long term relationship with you. And it's pushy of you to expect a second date when you haven't even made the main course.
Despite the fact that businesses are spending more and more money to get visitors to their site, 97% of new visitors do not convert the first time they arrive at your site. 
In fact, 73% of online shoppers agree that their path to purchase is more complex and less direct than it used to be.  We're actually making it *harder* for people to convert!
Think that getting people to register with your site increases the likelyhood that they'll return and purchase again? Think again! That password that you had people set up? Well 90% of people claim to have left a website when they forgot their login information.  That's a lost customer, not a retained one.
Want to increase your conversions rates? Make it easy for people to buy from you. It's so simple! Here's a few tips to increase your conversion rate:
- Remove mandatory logins before people can purchase from you.
- If you do ask for a password, make it optional, and not the first step in the funnel
- Whatever you do, DON'T require an email verification before people can buy from you
- If you do let people set up accounts, make the email address their login name. They won't forget that. Well, probably not. No guarantees.
Oh, and finally - Test! Don't assume that everything is going well. Always be running A/B testing to see if you can improve your conversion rates further. You never know how high you can push your conversion rates until you try.