By Charles Nicholls, founder and chief strategy officer for the consultancy SeeWhy

In 2011, the shopping cart abandonment rate continued its rise, reaching a new all-time high of 72 percent by the end of the year. In this blog, I'll try to answer why the shopping cart abandonment rate has risen, despite a focus on conversion optimization by many e-commerce sites. I'll also explain why I predict that the shopping cart abandonment rate will continue to rise in 2012.

Everything is more exaggerated over the holiday period: Retailers offer a dazzling array of new products, coupled with equally dazzling promotions, while trying to manage the constant problem of out-of-stocks. And customers make an abnormal number of purchases in a very short period and abandon their shopping carts in droves as they search for the best deals.

The 2011 holiday season was no exception. It was a bumper year again for e-commerce, with more than $37 billion in online spending in November-December, up 15 percent from 2010, according to comScore. And more than half of all online orders over the period had free shipping. While the volume was up, the average order value was down, reflecting widespread promotional offers.

Studying the shopping cart abandonment rate reveals interesting patterns in the run up to the holiday season.

As in previous years, many customers anticipated promotional offers and deferred purchases, causing the abandonment rate to shoot up, averaging 85 percent in the weeks running up to Cyber Monday.

Compare this with the average for 2011 of 72 percent, up slightly over 2010. The highest abandonment day of 2011 was at 89.2 percent on November 23, the Wednesday before Black Friday.

Discount Seeking Behavior

An e-tailing group study conducted at the end of 2011 found that 47 percent of online buyers would only buy discounted products, except under exceptional circumstances. The same study shows that 73 percent of consumers rate unconditional free shipping as a critical feature when making an online purchase.

What we can conclude from this is that customers are demonstrating "deal seeking" behavior. Given a difficult economic outlook in 2012, it seems likely that this will continue.

Abandonment Rates Keep Rising

The shopping cart abandonment rate rose steadily through 2011, as it has for the last three years. During this time, online marketers have not stood still: Checkout processes have been simplified, security seals added, more payment methods, and a host of other conversion rate optimization tweaks.

To answer why, you have to look at the different characteristics of abandoners and those that have never abandoned a shopping cart. In a consumer survey published at the beginning of last year, Forrester Research showed that 89 percent of online shoppers have abandoned their shopping carts. Abandoners have more experience online, make more purchases, and spend more time on the internet than those that have never abandoned a shopping cart.

More and more consumers are becoming sophisticated internet shoppers, aware of simple techniques to seek out the best deal and of TV-advertised price comparison websites.

This explains why, despite the significant improvements in conversion techniques on the majority of sites, shopping cart abandonment rates continue to climb.

One thing is clear: Customers are becoming increasingly savvy, looking online for information to make more informed choices, especially around price.