Trello was founded 2011 by Fog Creek Software (Stack Overflow founders), acquired by Atlassian in 2017 and integrated into Jira ecosystem. Trello's Kanban model — a row of lists (To Do / Doing / Done) + cards in lists (each card is a task) — is the productization paradigm of Kanban methodology, extremely intuitive; new users grasp it in 5 minutes. This simplicity is both pro and con: perfect for individuals / small teams / simple projects, but complex large projects (dependencies, sprint planning, time tracking) need more professional tools (Jira/Asana/Linear). API lets you automate nearly all Trello operations: create card / move card / add comment / attachment. Common use case: treat Trello as a lightweight task DB integrated into custom workflows. Post-Atlassian acquisition, Trello product iteration slowed; new-generation ClickUp, Notion took over young user market.