Bringing in more buyers

For those of you who are my fellow Etsians, I'm sure you've heard about a recent article written by some researchers at Wharton discussing the effects of free shipping on your shopping habits.  To me this is an enlightening idea.  I never thought about how the shipping fee changes my shopping patterns. 

Honestly, I never thought about this as something that has an effect on my online shopping...until I thought about it.  When I had my son, I signed up for Amazon Mom and got a free year of Amazon Prime.  Having the free shipping with Amazon, I started filtering my searches to only those items that were available for free shipping.  When I make purchases from fabric.com, I always order the minimum amount to get me my free shipping.  I could go on...  It really does effect my shopping habits.  I seek out free shipping and I have even been known to not purchase something online because I couldn't get free shipping.  Now that I am a eCommerce business owner, this is something I should probably consider, and definitely have not. 

I know when I started, my shipping fees were much higher.  Since then I have readjusted my shipping prices, but have not thought to provide many incentives for free shipping.  Perhaps this is a new incentive to offer over the holidays to see if it helps bring in some on line sales.  For a majority of my current sales, this is not an issue as the are mostly local.  I would hope that offering free shipping will attract new customers from across the country. 

I'm curious, has anyone used this and seen a significant sales difference?  Have you seen a difference even in comparison to a percentage discount?  What are you thoughts on the idea of free shipping?