What is the difference between the Trigger and Rules modules? Both the Trigger and the Rules modules provide many event-driven actions, but there are still several difference. What's the major difference between them? When should I pick one module instead of the other one?
Loosely speaking, Rules is much more generic than triggers. As Johan Falk mentions, "you could say Rules is an extended version of Triggers.. it is technically true, but does not really cover at full extent."