What Scite.ai does well
Scite.ai is a reference-management power tool. It labels citations in the literature as supporting, contrasting, or mentioning a given claim — very useful for verifying whether a paper's findings are upheld by subsequent work. Scite offers a notification feature for new citations to a specific article, and a Scite Assistant for Q&A over the literature. It's not primarily a topic-monitoring tool, though.
Smart citation classification (supporting/contrasting/mentioning)
Scite Assistant for literature Q&A
Browser extension and Zotero plugin
Strong citation graph