To date, adding semantic capabilities to web content usually requires considerable server-side re-engineering, thus only a tiny fraction of all web content currently has semantic annotations. Recently, we announced Reflect (http://reflect.ws), a free service that takes a more practical approach: Reflect uses augmented browsing to allow end-users to add systematic semantic annotations to any web-page in real-time, typically within seconds. In this paper we describe the tagging process in detail and show how further entity types can be added to Reflect; we also describe how publishers and content providers can access Reflect programmatically using SOAP, REST (HTTP post), and JavaScript. Usage of Reflect has grown rapidly within the life sciences, and while currently only genes, protein and small molecule names are tagged, we plan to soon expand the scope to include a much broader range of terms (e.g., Wikipedia entries). The popularity of Reflect demonstrates the use and feasibility of letting end-users decide how and when to add semantic annotations. Ultimately, ‘semantics is in the eye of the end-user’, hence we believe end-user approaches such as Reflect will become increasingly important in semantic web technologies.