What factors contribute to world completition?
Does the "World Completion" achievement and title includes the points of interest (Waypoints and Pois) inside dungeons or just WvW / Open World Points ?
No, dungeons do not count for world completion, nor do the Exploration achievements (for discovering every area on the map).
The only think you need to complete are all the PvE zones, and the 4 PvP zones -- yes, even though 3 of those zones are the same, you need to do them all.
Once you've done this, you can register your completion (and earn your gifts of exploration) by visiting the Chantry of Secrets in Bloodtide Coast.