Almost four years ago, Visa (NYSE: V) announced it would be buying CyberSource for $2 billion in an effort to expand its efforts online and allow it to enhance its "payment, fraud, and security management capabilities." Since then, we haven't heard much from this segment, but there could be huge opportunities for it in the years ahead.  

The forgotten acquisition
CyberSource began as a competitor to the PayPal unit of eBay (NASDAQ:EBAY), and the first question Visa's CEO at the time -- Joe Saunders -- addressed when the acquisition was announced related to that very thing: 

Of course we're paying attention to what PayPal as well as other companies are getting into the eCommerce space; and we are obviously concerned that would have an effect on our market share over a moderate or a longer-term period of time.

It's not exactly an apples to apples comparison, but PayPal is estimated to be worth $40 billion. With a $2 billion price tag, CyberSource looks pretty attractive if it even comes close to PayPal's size.

The sizable growth
While many have remarked that the sizable growth of PayPal is a reason for optimism for eBay, we hear almost nothing surrounding CyberSource at Visa, which itself has witnessed incredible growth.

As shown in the chart below, through the first six months of the year, Visa has watched its CyberSource transactions rise from 1.4 billion to 3.8 billion -- over 150% growth in just four years.

Source: Company Investor Relations.

The 45% growth seen in its processed transactions (which excludes those made using CyberSource) is also impressive, as that means it processed nearly 10 billion more over in the first two quarters of this year versus 2010. But what must be noted is that CyberSource formerly represented only 6% of Visa's total transactions, while it now stands at nearly 11%:

Source: Company Investor Relations.

The tangible benefit
Many have recognized the shift in the payments industry as cash is being used less and less. For example, the Federal Reserve recently found the number of checks written over the last 10 years has been cut in half, from 37 billion to 18 billion. Yet at the same time, purchases made using credit or debit cards had more than doubled to 73 billion. As a result, it should come as no surprise these shifting payment dynamics are beneficial to Visa.

But the CyberSource business allows Visa to benefit not only from the increased amount of credit and debit cards used in stores and in person, but also online. Forrester Research forecasts online retail sales in the U.S. to grow from $231 billion in 2012 to $370 billion by 2017, representing 10% of total retail sales, versus just 8% today. As a result, CyberSource is likely only going to continue its impressive growth.

Although it is difficult to determine the exact benefit of CyberSource to the bottom line of Visa, it's critical to know Visa has positioned itself to benefit from the shifting dynamics of both how (from cash and check to cards) and where (from in person to online) people pay for things. As a result, its impressive growth could be poised to continue for years and years to come.

Patrick Morris has no position in any stocks mentioned. The Motley Fool recommends eBay and Visa. The Motley Fool owns shares of eBay and Visa. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.