Future Internet is about combinations of communication, content and context services. Whereas the former two have achieved already a reasonable state of maturity, context information services are still at their infancy: at most stand-alone applications with limited on-line-or-off-line presence information. The critical success factor is still missing, namely context federation, which is the exchange of context information between different application, services and providers. This article investigates how context services could be successfully federated by following the same pattern that many other information and communication services have successfully followed in the past. First Context Information Aggregators and later Context Information Brokers play a critical role in addressing the market need for federated context information services. This article highlights challenges that have to be overcome to make this vision come true. If Europe takes the lead in overcoming these challenges, Europe can become a flourishing ground for a new context-brokering industry.