Now I'm no expert, so I've found the best review I could find on the internet, that I think perfectly sums up this movie.

The extract I've put here was written by Scott Tobias of the AV Club:

Picking up where the second entry, Dead Man's Chest, left off, the new film finds bland heroes Orlando Bloom and Keira Knightley teaming up with the once-dastardly Captain Barbossa (Geoffrey Rush) to find Johnny Depp's Jack Sparrow, who's trapped in Davy Jones' locker. Here's where things get confusing: Bloom and the gang must first go through Singapore to get a special navigational map from Chinese pirate Chow Yun-Fat, who's one of several pirate lords who must unite in order to secure pirate freedom in the Seven Seas. (There's also some business about a "Brethren Of The Coast," and the "nine pieces of eight," but let's not get ahead of ourselves.) Meanwhile, the East India Trading Company has possession of Davy Jones' beating heart and has brought Jones and his Flying Dutchman ship into its quest to eradicate pirate-kind. And then there's Sparrow, whose predicament has left him with several metaphysical manifestations.

The Pirates Of The Caribbean trilogy-and At World's End especially-stands as a lesson in the perils in blockbuster filmmaking: What started out as a fleet one-off swashbuckler with novel supernatural elements has become loaded and graceless, with each new entry barreling across the goal line like William "The Refrigerator" Perry. The franchise's two chief assets-the surprise of Depp's swishy pirate and Gore Verbinski's dexterity at directing slapstick action sequences-have been eclipsed by expository scenes that confuse even more deeply in their attempt to clear things up. Should the franchise warrant still another sequel, the dialogue might as well be in Esperanto.

The full review can be found at:
http://www.avclub.com/content/cinema/pirates_of_the_caribbean_at

They started filming without a finished script.

There's a bonus scene at the end of the credits.

Release prints were delivered to theaters with the fake title "Rummy 3".

In the scene where Jack the Monkey is sat shivering, that was done by placing the monkey on a vibrating box.

There was an actual council of pirates at one time in history.

The Jolly Roger Jack flies from his dinghy at the end of the film is a variation on the one flown by historical pirate Henry Every.

The Green Flash is a real but very rare optical phenomenon during sunrise or sunset that is best observed at sea. It is caused by the refraction of light in the atmosphere, amplified by a mirage.

The sword used by Davy Jones to kill Will Turner is the sword Will made for Admiral Norrington in the first movie. It is returned to Norrington in this movie and he stabs it into Davy Jones when he is killed.

Whether you think Pirates of the Caribbean 3 is good or bad is up to you, but nobody can argue the series has had a profound impact on popular culture. It is not just a film, but an event, it is one of those that every so often you and will friends will venture out to see. It is a social gathering, a talking point, something you do noy want to miss out on even if it is one huge mess.

Yes, its rubbish. But its rubbish with style.