Look on your desk. Almost every desk has a cup that is filled with pens. Maybe you got those pens from various clients or at a trade show, but that cup holds them all for those moments you need them most.
You may have one or two pens you prefer to use, but still the cup is pretty full and there are times you will simply grab the first pen that your fingers touch. It can be disappointing when that pen doesn't work or it can provide a surprise when it is one you haven't tried, but works very well.
This is a concept for ecommerce. No, you don't necessarily have to toss out free pens, but there is an idea about working to become a favorite of customers.
Why not encourage visitors to add your website to their favorites folder. Allow consumers to think of your site the same way they think of their pen cup.
This is a call to action and may not make sense on the first or even second tier pages of a website. It should certainly be added by the time the consumer reaches the checkout.