An Overture and comScore study on search keywords found that only one percent of electronics category purchases occurred in the same browsing session as the search click, according to ClickZ. An additional seven percent happened as a latent visit to the e-commerce site. A full 92 percent of purchases happened offline. Across all categories, such latent purchases accounted for 85 percent of e-commerce, which means that most will go unrecorded by online marketers, who generally track ROI based only on immediate sales.

In a separate finding, the study indicated that the vast majority of online purchases related to keyword searches come after using generic search terms, rather than branded search terms. While this seems to contradict the common wisdom that branded keywords are more effective in reaching people about to buy products, the results may actually be consistent. Branded keywords do have a higher ROI, although - due to low keyword inventory levels - they are responsible for a lower proportion of sales. But people coming in from branded keywords typically started off their search with a broader set of search terms.