Jobs may still be hard to come by, but that’s not stopping Americans from spending their money, according to a report from comScore, which found that total e-commerce spending in 2010 reached $227.6 billion, up 9% from 2009.  ComScore’s Digital Year in Review report was released Monday night and takes a look back on the major tech trends and surprises that emerged in 2010.  One of the most notable e-commerce trends to emerge in 2010 was the group buying/flash sale phenomenon.

So which site led the fray?  All together now: Groupon.  After pioneering the group-buying space little more than two years ago, the site saw some pretty astounding growth in 2010.  Groupon’s website drew 10.7 million unique visitors in December 2010, an increase of 712% from 2009.  LivingSocial also saw some interesting growth last year.  In December 2010, 5.7 million unique visitors dropped by LivingSocial, representing an increase of 438% from the year before.

Both sites have been in a head-to-head battle for subscribers over the last year, and both have made sizable gains in the market while hundreds of Groupon clones have spread like fungus across the globe.  Today, Groupon has some 46 million subscribers around the world, compared to 1.8 million in December 2009 and just 3,000 in December 2008.  (Can Groupon reach one billion subscribers in December 2011?!  Probably not, since that would be one-sixth of the world’s population…and at least some of those people are die-hard LivingSocial fans.)

Similarly, LivingSocial has seen some significant growth.  In fact, the company’s recent Amazon gift card promotion (in which subscribers could buy a $20 gift card for $10) resulted in a surge of traffic, and the company now claims that its subscribers number in the 20 million range.  This would mean that the number of LivingSocial subscribers literally doubled from October, when the company counted 10 million subscribers.

In the flash sales category, Gilt Groupe took the lead with 863,000 unique visitors in December 2010, marking an increase of 52% from December 2009.  Gilt was followed by HauteLook, Ideeli, and RueLaLa, but while RueLaLa saw the lowest number of unique visitors in December 2010 (435K), it represented an increase of 33% over 2009. 

Image source: comscore.com