The "last ad" or "last click" concept refers to giving credit for a conversion exclusively to the last ad that a prospect acts upon.
For example, if a visitor to your company Web site was referred to you from Google, you may give Google (or your Web site) all the credit for bringing that visitor to you. In fact, there are many influences that may have brought that visitor to your Web site downstream from Google. The visitor may have read an article about your company's product in an e-newsletter, saw your company on a third-party industry Web site (yes, like GlobalSpec), been referred by a colleague…the list goes on.
Research conducted of more than 700 industrial buyers showed that when searching for a specific company – one that they know by name – they often type the company name into a general search engine box rather than typing the url directly. In fact, two-thirds of the buyers type the company name in the search box at least 60% of the time when visiting the Web site of a company they know. So when you see Google as the referring site, you need to ask yourself, "How did the visitor find out about my company?" It is likely that many of the forms of advertising, public relations and marketing tactics you employ had an influence (unless of course you work for a company that is a household name).
The point of this is you don't want to lose sight of the various phases of the buy cycle and the need to have a your brand represented at all stages and in various media and methods.
To read more about the last ad concept and to get the latest research on how industrial professionals are buying product and services, download the white paper: "Understanding the Industrial Buy Cycle: How to Align Your Marketing with Your Customers' Buying Process."