Karen M. Estlund’s dissertation A Media Archaeology of Online Communication Practices through Search Engine and Social Media Optimization constitutes a sophisticated interrogation of the invisible infrastructures governing digital communication in contemporary networked societies. Rejecting technologically neutral interpretations of online information systems, the thesis advances a historically grounded media archaeological framework through which search engine optimisation (SEO) and social media optimisation (SMO) are reconceptualised as political, cultural and technical practices embedded within structures of algorithmic governance. Estlund argues that access to information on the contemporary web is not direct but mediated through powerful digital gatekeepers such as Google, Facebook and Twitter, whose proprietary algorithms regulate visibility, legitimacy and discoverability. Through this lens, optimisation practices become more than marketing techniques; they emerge as mechanisms through which communicative actors negotiate institutional control over online discourse. Drawing upon Shannon’s mathematical communication theory, cybernetics, gatekeeping studies and critical information politics, the dissertation demonstrates how HTML structures, metadata systems, semantic markup and hyperlink architectures collectively shape communicative accessibility. Particularly illuminating is the empirical analysis of archived Los Angeles Times webpages and U.S. Senate campaign sites, which reveals how journalistic and political institutions progressively adapted their textual, structural and metadata strategies to comply with evolving algorithmic preferences. Estlund further exposes the ideological tensions surrounding so-called “black hat” optimisation practices, arguing that distinctions between legitimate and illegitimate visibility strategies are largely defined by corporate platform interests rather than purely ethical criteria. The dissertation’s principal contribution lies in repositioning SEO and SMO as historically situated sociotechnical communication practices that materially influence public knowledge circulation, political participation and informational authority. Ultimately, the thesis demonstrates that digital visibility is neither natural nor democratically neutral but instead produced through contested infrastructures of optimisation, regulation and institutional power that continuously shape the conditions under which contemporary communication becomes visible, searchable and socially consequential.