Shimon Sandler offers some tips for linking phone orders to search campaigns, ranging from simple (using a pay-per-call provider) to more involved (setting up a database of unique promo codes tied to specific keywords).
You can create a unique landing page for each product that features a different phone number for each of the engines, or add a promo/reference code to each product page and train your phone sales reps to ask for and record this code for every order.
Sandler says that you can also put a printable coupon on each landing page that consumers need to redeem in-store, or try an IVR phone system that tracks phone calls and their sources. - Read the whole story...