SkillStack - Spaced-repetition tracker for developer skill files

Problem: Self-taught developers accumulate a sprawling library of personal notes, code snippets, and learning journals, but that hard-won knowledge decays. The HN threads in this brief show the underlying anxiety directly: developers feeling shallow when they see what others build, generalists worried about which skills survive a downturn, newly promoted managers scrambling to absorb new competencies while still coding. The common thread is that people are constantly learning but have no system to make learning stick. Solution: SkillStack organizes your personal skill notes into a spaced-repetition review queue, so the concepts you invested hours to understand resurface at intervals that keep them sharp and searchable. Named product: SkillStack sits on top of the plain-text skill files developers already keep. Instead of forcing a new note-taking paradigm, it treats existing notes as review candidates and layers a scheduling engine on top. MVP: import a folder of markdown skill files, tag reviewable sections, generate a daily review queue with spaced-repetition intervals, and provide full-text search across the whole stack. Revenue: a B2C SaaS subscription, likely a low monthly price with a free tier capped by number of tracked files or reviews per day. GTM: launch on HN and dev communities where the audience already congregates and openly discusses skill retention. Growth loops: shared public skill decks and review-streak sharing could drive some referral, though this is a personal-productivity tool at heart so word of mouth among self-taught developers is the primary loop.