There is one thing though that is stunting bitcoin's growth in online shopping (where it's most likely to make an impact first): credit card rebates. Virtually all credit cards people use nowadays offer some sort of point/cashback system, which is, of course, paid from the retailer's pocket in terms of outrageous fees. It should be in every retailer's best interest to offer significant incentives to use bitcoin, in terms of fee savings: even something crazy as 5% cash back on all purchases, forever when paid in BTC would probably result in net savings for most retailers. Other creative things: free giftcards (instead of cashback) for even more retailer margin, drawing for cool and awesome items when bill is paid with BTC, etc etc.