With the help of PayPal, eBay (NASDAQ:EBAY) is making the world of online shopping a whole lot simpler.

Log In With PayPal takes a single user login ID and proliferates it across the world of online commerce so a buyer can make secure purchases without entering much more than a login ID and password. On the backend, PayPal sends all of the pertinent credentials to the merchant so that the buyer doesn't have to. In the context of mobile, Log In With PayPal revolutionizes the mobile online shopping experience since it eliminates as many required fields as possible.

It's a win-win
Before you start busting out those PayPal jokes about this being a nightmare for sellers, bear in mind that both parties stand to benefit.

Buyers no longer have to remember a swath of login credentials associated with shopping at multiple sites, which could be viewed as a huge convenience factor. Sellers stand to benefit from a more streamlined online checkout experience, which is likely to improve shopping cart abandonment rates. This is especially true for mobile devices, where filling in required fields isn't exactly ideal.

Two fronts, one face
The opportunity is for PayPal and eBay as a whole is quite tremendous, considering the company is attacking commerce from both online and offline fronts. As a result, eBay estimates its addressable market has expanded to $10 trillion, of which it expects to enable $300 billion of global commerce by 2015.

When you boil it down, PayPal and eBay are addressing the challenges associated with increased online commerce growth across the world (not to mention shopping on a mobile device). If PayPal has its way, the days of remembering all multiple login credentials to shop will become a thing of the past.

I suppose you could consider this another reason to buy eBay today.