How are you measuring your eCommerce promotions' advertising and breakeven?

Historically, the catalog industry has measured the response rate for various promotions, the advertising cost of the promotion and its breakeven based on demand, product cost etc.  Along comes the eCommerce world and many of the new promotional methods (such as email, affiliate programs, etc.) are apparently not being measured.

At the same time, companies that were traditionally catalog oriented are spending 25% to 35% of sales for catalog advertising costs to create, print and mail catalogs.  On the other hand, while the eCommerce programs are much cheaper, our research shows they are spending 2% to 15% of net sales on eCommerce promotions.

The problem today is that the eCommerce costs are additive, incrementally.  It's not an offset to the catalog costs.  And at the same time businesses have not been able to decrease catalog costs or eliminate the catalog without severely cutting sales.

Tell us how you are measuring your eCommerce promotions in terms of advertising and breakeven...