Consider this the abbreviated version of the buying cycle: a shopper wants things, even things she doesn't know she wants, and she seeks these things out or they seek her out as she goes about her daily life. In the marketing continuum, there is a point at which she goes from wanting to acquiring, whether by force or by fare.
That brief point in time is known as the moment of aperture - the opening where the buying decision has been made and the resources to acquire that thing are available. The exchange of the thing with the resources is known as the transaction. Moment of aperture and transaction - keep these terms in mind.
Before the current economy, the moment of aperture was not always aligned with the transaction. Many times, the gap between the moment of aperture and the transaction was long enough that the aperture closed before the transaction was available. This meant that the transaction was lost.
We don't have to go back into history very far before we see a much slower "economy." Charts, statistics, and government data show that the number of transactions in one day today (in many industries) equals a total year of transactions only 40 years ago.
With the automobile, the plane, the computer, and the Internet - we see an acceleration in not only moving people, but the speed at which we can acquire those things we desire. Transportation allows us to "get around" faster and visit places such as the mall. The computer allows the transaction to occur faster and eventually, at a reduced cost. Now the Internet has removed most barriers to transaction. When a person has a connection between his device and the desired commodity, the transaction can occur in as little as one click (think Amazon). Therefore, the moment of aperture and the transaction are almost simultaneous.
A simple look at the psychology of the purchase reveals that the moment of aperture isn't just a single moment in time, but a slow or maybe not-so-slow "opening" of the human mind to consider the commodity, desire it, and then determine to purchase it. There's more to it than this, but in simple progression, this is how the buying decision evolves in the human brain. Where it can get more complicated is after the decision to buy the commodity is made, there is a decision from whom it will be purchased. This is where the buyer has to make a decision to buy from seller A or seller B.
Therefore, assuming you buy my argument that the Internet is the medium that has closed the gap between the moment of aperture and the transaction, then such is the place where we need to most convince the buyer to purchase from us versus the competition. And if playing the price-only/commodity game isn't your thing, then there is but one strategy to use: positioning.
Positioning is the ONLY strategy that fights for the prospect against your competition. So rather than simply showing parts inventory or product descriptions on your website, it's critical that each page clearly communicates your position and you provide the prospect with the easiest path to acquiring the thing you are selling.
If you can sell it online, do so. If you can't sell it online, provide a tool, wizard, or application that puts the prospect as close to the transaction as possible. Remember, the longer you make the prospect wait between the moment of aperture and the actual transaction, the higher percentage of attrition you'll experience. Even with e-commerce, there is a very high percentage of "cart dumping" that occurs. So take the opportunity to seed your position in the mind of the prospect and then take away as many barriers and lapses in time as you can before the transaction occurs. That's when you'll know you have a great sales engine!