The two most common techniques most ecommerce sites use for driving traffic are SEO and SEM (AdWords, etc). Some more progressive sites are using social media, Twiiter accounts, Facebook fan pages, and Facebook advertising, with varying degrees of success. You hear less about the paid shopping comparison engines. For those who don’t know how they work here’s a quick primer (remember there are plenty of exceptions to every rule).

I’ll use the Australian market for examples as it’s the one I’m most familiar with, but the principles apply everywhere. Australia has a few shopping comparison engines: the homegrown GetPrice.com.au and Shopbot.com.au, as well as the Ebay owned shopping comparison behemoth, Shopping.com. There’s also a few smaller players.

The process goes something like this. You setup an account with them. You need to get your products to them somehow. Unless you have a very small number of products, the best way to do this is with an automated feed – XML, CSV or similar. Most shopping comparison sites support 2 or 3 formats, usually similar to each other but unfortunately usually not identical. Your shopping cart software may have a module already to provide a feed for these sites. If not, it’s a relatively small job for a decent programmer to make one. The shopping site sucks up all your products and puts them in appropriate categories. For example, if you have a women’s fashion site, you might have a bunch of products end up in the leggings category.

They get traffic, typically through a number of means including SEO, SEM, and doing distribution deals with other sites such as Yahoo! or other popular portals. People come to the site, typically to a product comparison page. They click through, and end up on your site. You pay when someone clicks.

The great thing is because they tend to attract relatively qualified traffic, the sites convert well and often have a better conversion rate and lower cost per click than AdWords.

If you aren’t using shopping comparison sites, I recommend you investigate them.