Online shoppers are generally not going directly to an online retailers website.

Instead, consumers are accessing products online through search engines and price comparison engines such as Google Shopping, Amazon Product Ads and Pricegrabber.

What are Price Comparison Engines?

Online shoppers are a frugal bunch. Customers want items quickly, and from the cheapest reliable seller. Price comparison engines or comparison shopping engines (CSEs) group products together based on price, shipping rates and seller ratings so consumers can compare products easily in one place.

If for example, I’m shopping for a GoPro camcorder online, Google and the other comparison engines have comparison pages which outline the different sellers which have this product, and what each is charging:

Shoppers who click through on the seller listing your go directly to your site, and the comparison engine charges you a pay per click (PPC) for that visit.

How Do I list on a Comparison Shopping Engine like Google Shopping?

To get your products on comparison engines, you need to send your product information to the shopping channels using a beefed up excel file or product data feed. Each price comparison site has its own feed format and requirements, so be sure to check out the specifications beforehand.

The comparison engines then list your product on those comparison pages based on what they think the user is looking for (e.g. Google’s algorithm) and what you are bidding for products and product categories. I don’t want to delve into bidding strategy, but you can check out some comparison shopping engine bidding best practices here.

Top 3 Comparison Shopping Engines

Each quarter, we break down the top 10 Comparison shopping engines, based on metrics like traffic and revenue.

1. Google

Even though Q4 2012 was the first quarter which was fully paid for Google Shopping, the engine still brought home the gold overall, and in many individual engine rankings including merchant tools, traffic and revenue. Google Shopping only ranked fourth overall for conversion rate, and got pummeled in merchant responsiveness, but ultimately beat out all the other engines for the holiday quarter.

Google Shopping is a must-list engine for ecommerce merchants who have the ability and the budget to list on this engine.

2. Pricegrabber

If you are already listing on Google Shopping, and you are looking to expand onto some additional paid engines, Pricegrabber is definitely an engine to consider. Right behind Google, Pricegrabber generated the second highest amount of traffic, and the second lowest cost of sale among the comparison engines.

3. Nextag

Nextag is another paid engine for online marketers to consider listing on. This past holiday, Nextag had the second highest revenue of all of the comparison sites, and the third highest traffic and conversion rate.

What are Comparison Shopping Sites and How Do I List on One?

Comparison shopping engines condense products based on price so consumers can sort while online shopping.

To list on a shopping comparison site:

• Create a product data feed
• Check out PPC bidding best practices
• If you’re just getting started with the comparison engines, Google Shopping is a good place to start.