  We begin with a brief sketch of the history and evolution of search engines, from their conception in the pre-Internet era to the development and implementation of contemporary (“Web 2.0” era) search engines such as Google. Our examination of important historical developments of this technology is intended to address our first question, noted above: “What is a search engine?” It also provides a backdrop for analyzing our second major question, “Why are search engines problematic from an ethical perspective?” where a cluster of ethical concerns involving search engine technology is examined. These include issues ranging from search engine bias and the problem of opacity/non-transparency, to concerns affecting privacy and surveillance, to a set of issues involving censorship and democracy. We also describe some emerging ethical concerns affecting (cyber)security—at the data, system, and (inter)national levels—generated by the use of “discoverable search engines” in the context of the Internet of Things. Additionally, we question whether search engine companies have any special moral obligations, e.g., in light of their “privileged” placed in society as “gatekeepers of the Web” (Hinman, 2005, 21), for which they should be held accountable. In analyzing this question, we also examine a key role that trust now plays for users who have come to depend on search engines, and the companies that develop them, for access to accurate information.