AusGamers attended a small pre-E3 event hosted by Ubisoft and had a chance to get up close and personal with a demo of Assassin's Creed: Black Flag.
From their preview:
As pirates, you and your crew obviously aren’t aligned to anyone but your own desire for all the phat lewts, but the game does offer up factions by way of the warring Spanish and British, both of whom you can engage as you see fit, but you can also just leave them alone to sort out their own issues. This allows you to simply come in and pick off the limping winner, or enjoy the leftover spoils of battle -- either way, being a somewhat neutral party in the series does present itself with exciting opportunities. For example, you can engage in taking over island forts, manned by either of the aforementioned factions.
These are basically mini-games, or “meta-games”, which have become a staple distraction in the series in the past few entries. And, like another recently-released Ubisoft title, taking over these strongholds will reward with bonuses to your growing armada, where you can even attempt to lure the enemy into each fort’s comfort zone so they attack on your behalf. In fact, there’s a seminal third faction working against you and others in the game, by way of treacherous weather, which you can also use to your advantage and lure the enemy into..."