The status-quo of misinformation moderation is a central authority, usually social platforms, deciding what content constitutes misinformation and how it should be handled. However, to preserve users' autonomy, researchers have explored democratized misinformation moderation. One proposition is to enable users to assess content accuracy and specify whose assessments they trust. We explore how these affordances can be provided on the web, without cooperation from the platforms where users consume content. We present a browser extension that empowers users to assess the accuracy of any content on the web and shows the user assessments from their trusted sources in-situ. Through a two-week user study, we report on how users perceive such a tool, the kind of content users want to assess, and the rationales they use in their assessments. We identify implications for designing tools that enable users to moderate content for themselves with the help of those they trust.