What aggregators do provide is visibility into marketing performance. Using Zalando as an example, management said it spends around 2% of sales on marketing on the platform and applies the same requirement as elsewhere: marketing must clear a return hurdle to justify the spend. The company said it can spend profitably on aggregators and does so, but the feedback it receives is primarily on the return from marketing activity rather than on who the end customer is.On aggregator websites, management said it re ...