According to iMedia, between 70% and 90% of all consumers buying “high consideration” products begin their research online, and then purchase offline.
+Create a unique landing page for search advertising
+Establish an 800 number, accessible only from this landing page
+Track sales generated by the 800 number
Another option is to create a unique landing page for each ad provider (one landing page for Google AdWords, one for Overture, and one for FindWhat). Conversion tracking can be done by measuring the incoming 800-number calls or the customer reference code.