The recent evolution towards hypermedia-driven services, Linked Data, and the Web of Things is turning the Web into a homogeneous hypermedia fabric that interconnects everything – devices, physical objects, documents, or abstract concepts. The latest standards on the Web of Things and (Social) Linked Data allow automated software clients to navigate, query, observe, and act on this uniform hypermedia fabric. Use cases that have long been envisioned for artificial agents on the Web – as published in the original Semantic Web vision in 2001 and going back to the early days of the Internet – are now closer to their practical implementation and deployment. Nevertheless, the engineering of such modern Web-based systems poses research challenges that have yet to be addressed.