The vision of the Web of Things (WoT) aims to leverage Web standards in order to interconnect all types of embedded devices and real world objects, and thus to make them a part of the WWW. Therefore, WoT aims to build a future Web of devices that is truly open, flexible, and scalable. We aim to contribute towards achieving this goal by relying on existing and well-known Web standards used in the programmable Web (e.g., URI, and HTTP) and the semantic Web (e.g., RDF), in order to enable the Web integration of Robot Operating System (ROS) devices. In particular, we motivate the problem of integrating ROS devices in Web environments, elaborate on the integration potential, and describe specific application examples. We provide a mapping between ROS and REST concepts and interaction primitives. In addition, we show how REST is capable to enhance a mapping of the ROS architecture in terms of complex resources and hypermedia. The contributions described in this paper pave the way towards realising a WoT, where ROS devices can be easily accessed and directly integrated by using standard Web technologies, without additional custom implementation effort or having to add intermediate communication layers.