Today's web personalization technologies use approaches like user categorization, configuration, and customization but do not fully support individualized requirements. As a significant portion of our social and working interactions are migrating to the web, we can expect an increase in these kinds of minority requirements. Browser-side transcoding holds the promise of facilitating this aim by opening personalization to third parties through web augmentation (WA), realized in terms of extensions and userscripts. WA is to the web what augmented reality is to the physical world: to layer relevant content/layout/navigation over the existing web to improve the user experience. From this perspective, WA is not as powerful as web personalization since its scope is limited to the surface of the web. However, it permits this surface to be tuned by developers other than the sites' webmasters. This opens up the web to third parties who might come up with imaginative ways of adapting the web surface for their own purposes. Its success is backed up by millions of downloads. This work looks at this phenomenon, delving into the "what," the "why," and the "what for" of WA, and surveys the challenges ahead for WA to thrive. To this end, we appraise the most downloaded 45 WA extensions for Mozilla Firefox and Google Chrome as well as conduct a systematic literature review to identify what quality issues received the most attention in the literature. The aim is to raise awareness about WA as a key enabler of the personal web and point out research directions.