We all know the schpeal about "the long tail" of search: low-cost clicks, high conversion rates, and, while the volume of traffic on each term is low, if you glue enough of those low traffic terms together the impact is material. The engines hate long tails. I recently heard a Googler say that anyone who mentions the long-tail at Google has to put a dollar in a jar. That's understandable, those tails eat up a huge proportion of Google's computing power for a relatively small amount of revenue. It's one of the reasons for the ever expanding breadth of broad match. "You folks don't worry about keywords, we'll just take a peek at your site and serve your ad whenever we think it's appropriate..." Savvy marketers know better: segmentation is the key to success in cataloging, emailing and search as well. The more granularly you can measure and manage the ROI of these segments, the better the performance of the program. But how do you know if your tail is long enough or whether you're getting as much out of it as you could? We thought sharing some rules of thumb and benchmarks might be helpful. One general rule is that you should have 5 to 10 keywords per sku on your site. If the skus are all in a few narrow categories that multiplier may be much lower: you might carry 100,000 different nuts and bolts, but find that 50,000 keywords gives you comprehensive coverage for the way people search for your products. You may carry only 500 one-of-a-kind items, and need 100,000 keywords to cover all the ways people might describe them. The number by itself doesn't guarantee quality. You can easily quadruple your term list by adding "shop for...", "buy...", "...online", "...store" prefixes/suffixes to the existing list without adding any meaningful variation. It's useful to have a smart human scan the full list periodically to look for holes, missing synonyms, etc. The real measure of the tail is how well it performs. Does the tail drive meaningful volume? Are the tail and the head equally efficient or close to it? Making the tail work for you is a product of having:
- Quality terms, not just quantity
- Smart classification schemes. The two-tiered hierarchy of campaign and adgroup, is insufficient to this task. We'll talk more about that in a subsequent post.
- Smart bidding algorithms, that can handle low traffic keywords correctly
- Wise use of match-types, to prevent the engines from simply serving your high traffic terms on every search
Join the Discussion