Devices, people, information and software applications rarely live in isolation in modern building management. For example, networked sensors that monitor the performance of a chiller are common and collected data are delivered to building automation systems to optimize energy use. Detected possible failures are also handed to facility management staffs for repairs. Physical and cyber security services have to be incorporated to prevent improper access of not only HVAC (Heating, Ventilation, Air Conditioning) equipment but also control devices. Harmonizing these connected sensors, control devices, equipment and people is a key to provide more comfortable, safe and sustainable buildings. Nowadays, devices with embedded intelligences and communication capabilities can interact with people directly. Traditionally, few selected people (e.g., facility managers in building industry) have access and program the device with fixed operating schedule while a device has a very limited connectivity to an operating environment and context. Modern connected devices will learn and interact with users and other connected things. This would be a fundamental shift in ways in communication from unidirectional to bi-directional. A manufacturer will learn how their products and features are being accessed and utilized. An end user or a device on behalf of a user can interact and communicate with a service provider or a manufacturer without go though a distributer, almost real time basis. This will requires different business strategies and product development behaviors to serve connected customers' demands. Connected things produce enormous amount of data that result many questions and technical challenges in data management, analysis and associated services. In this talk, we will brief some of challenges that we have encountered In developing connected building solutions and services. More specifically, (1) semantic interoperability requirements among smart sensors, actuators, lighting, security and control and business applications, (2) engineering challenges in managing massively large time sensitive multi-media data in a cloud at global scale, and (3) security and privacy concerns are presented.