Top 10 Comparison Shopping Engines

The March issue of Website Magazine included an article about optimizing for comparison shopping engines, entitled CSEs by the Numbers. A leading resource in the CSE space is CPC Strategy, which ranks the top comparison shopping engines serving the U.S. market on a quarterly basis.


The criteria used in the rankings include overall traffic driven; average amount of revenue generated; conversion rates; cost of sale percentages or return on spends; average CPC rates, responsiveness rates and quality of merchant tools. Below is the data and analysis compiled by CPC Strategy during the fourth quarter of 2010, and the Q4 CSE Rankings appear at the bottom of the post.


For the first two categories, the results are based on an index of 100, with the rest expressed as a percentage of the leader. Other notes of interest include the following:


  • "Google" refers to Google Product Search and does not consider Google's organic listings or their paid offerings like Adwords or Product Listing Ads
  • Similarly, Bing Shopping refers to just the shopping portal that Bing offers, and not Bing the shopping engine
  • Amazon Product Ads is a separate entity from the Amazon Marketplace. The primary difference is that Product Ads lead a customer off of Amazon's site, whereas on the Marketplace the purchases are made directly on Amazon's site





Google Product Search takes the early lead here by a healthy margin over the rest of the engines. With a lot of holiday shoppers beginning their search on the most popular search engine, many found what they were looking for directly on Google and ended their searches there. The biggest jump here was by Amazon, which since introduced has gone from a 2nd-tier engine in terms of traffic driven to CPC Strategy's second-most trafficked engine during the fourth quarter of 2010.


While Google is by far the largest search engine on the internet, Amazon is by far the largest retailer on the internet, so it was only a matter of time before its Product Ads solution caught up with Amazon's great reputation.


With Google and Amazon taking most of the share in this quarter's rankings, most of the other engines saw drops in relative share as a result, except for Bing Shopping which, like Google, is itself powered by a popular search engine.





Google continues its trend of being the top dog while the others saw drop-offs.


The data below is broken into two parts, dark blue represents data from Q4 2010, and light blue reflects data from Q3 2010.


Conversion Rate % (orders/clicks)



Even though they've ended their popular Cashback program, Bing Shopping remains CPC Strategy's best converting engine along with its search engine brother Google, but Bing suffered a slight drop due to the lack of Cashback incentives. Nextag is the leader among paid engines but as we see in the rest of the list, every CSE but Amazon (which saw great conversions in Q3) saw improved conversion rates due to the holiday season. PriceGrabber saw the most dramatic improvement with nearly a half-percent gain from quarter to quarter.


COS % (Cost divided by Revenue)



Once again, other than the free engines, Amazon takes top honors as the best performing engine based on ROI. Still, similar to the conversion rates, the overall COS improved in spite of the CPC rate changes, with the exception of Amazon.


Average CPC (cost-per-click) Rate



A controversial subject for many, the Q4 shopping season represented a time when CSEs raised their rates as demand and traffic ramped up for the holidays - some by as much as 25 percent across the board. Become and Amazon, like the free engines, saw no rate increases. Others, like didn't raise rates across the board but only for some of the categories, so their overall CPC rate didn't change as dramatically as the others.


Shopping Engine Responsiveness Rating (ranking from 1-10, 1 being best)


  1. Become
  2. PriceGrabber
  3. Shopzilla
  4. NexTag
  5. Shopping
  6. Amazon Product Ads
  7. Pronto
  8. TheFind
  9. Bing
  10. Google Product Search


In spite of being a smaller engine, once again tops the rankings as being the most responsive by not only answering all questions in a timely manner but by taking initiatives as well - though the same can be said about most of the top CSEs on the list.


Merchant Tools (ranking from 1-10, 1 being best)


  1. Google Product Search
  2. Shopzilla
  3. NexTag
  4. PriceGrabber
  5. Become
  6. Shopping
  7. Pronto
  8. Amazon Product Ads
  9. TheFind
  10. Bing


For purposes of the rankings, Google Product Search is represented by its cousin Google Analytics. The tools that an engine provides are a crucial part of running a successful campaign. While most CSEs provide similar tools for tracking cost and revenue, some go above and beyond to provide the necessary resources to push a campaign's success to its limits.


For instance, Shopzilla allows a merchant to not only see product and category performance but be able to bid specifically on those as well. Amazon Product Ads is the only paid CSE that does not have its ROI tracker, so the only way to track orders generated from clicks made there is through a third-party tracker. Also lacking from the Product Ads login is the ability to run SKU reports over custom timeframes, which is also crucial for monitoring how a specific product is doing. Being a relative newcomer to the CSEs, they have come a long way but there's still a gap between them and the longer established engines.




In the end, CPC Strategy ranked each shopping engine from each of the metrics from 1-10 and assigned a point value for each category (higher being better). They doubled the COS percentage value, making that out of a possible 20 points, and weighted traffic + revenue as 1.5 each for a maximum of 15, summed it up, and got the following:



Google runs away with it, leading in a few key categories, with Nextag in second. Not far behind them is Shopzilla, along with Amazon, which isn't bad at all for an engine that less than two years ago was essentially non-existent. CPC Strategy emphasizes that each engine has its own strengths and that managed properly it makes sense to be listed on as many as you can - and they continue to vouch that these are the top 10 shopping engines to be on.