More effective than email, the returns on this used-to-cost-too-much channel keep improving - especially for companies in feel-good product categories.

The $500 million deal highlights the inherent challenges of creating digital luxury supermarkets.

A reported $5.8 billion bid for Macy's has raised the old question: Does anybody need department stores?

Rationalizing investment in these fast-growing networks is still far too tricky for advertisers.