Unique Selling Proposition. It is generally accepted that, for online sales to happen, a site must have a USP. In other words, there must be a reason for people to buy from that site, rather than from its competitor. GoDaddy.com is not the only domain registrar, but they offer domains comparatively cheaply, they have pretty girls on the homepage 😉 and they have a fancy domain management area for their customers. Any or all of these can be considered the GoDaddy USP.