It may sound obvious, but

It may sound obvious, but a new study shows that the single most important factor for online profitability is customer loyalty — getting customers to come back regularly. In fact, most online retailers lose money on one-time shoppers.
To earn customers’ loyalty, the study’s authors recommend, treat them as assets — not just transactions — and provide them with real value.
Customer Loyalty Key to E-Commerce Profitability

It may sound obvious, but