Awesome, Dear Boy: Frank Langella considers Dawg to be one of his three favorite roles (the other two are Richard Nixon and Skeletor), because he got to not only be a pirate, but a scenery-chewing over-the-top bad guy pirate. Apparently, the man loves being able to just go for broke in a role.
Creator Killer: Cutthroat Island bankrupted the studio Carolco, as well as destroying Geena Davis' career and her then-husband Renny Harlin's respectability as a director (only the distributor came out rather unharmed). The flop of this film (as well as that of The Long Kiss Goodnight, also starring Davis and directed by Harlin) is widely credited with destroying their marriage, as Harlin had pushed for Davis, then known for comedic roles, to headline the two blockbusters.
Genre-Killer: Some have accused the film of being this for swashbuckling pirate movies. In reality, the genre was already dead at the time. Cutthroat Island just failed to revive it. We would not see another swashbuckling pirate movie from a major studio until Disney released Pirates of the Caribbean: The Curse of The Black Pearl in 2003.
Money, Dear Boy: The filmmakers, who really weren't invested in the project, made it anyway, because the budget was already secured by investors beforehand and they were contractually obliged.
Playing Against Type: Harlin hoped this movie would turn Geena Davis, an actress that had made her career on light romantic comedies, into an action star. It failed.
Star-Making Role: Despite the film flopping, it got John Debney (who mostly had been a television composer before this) noticed in the film scoring circles and launched his career.
Troubled Production: Michael Douglas conditioned his appearance on getting an equal amount of screen time as Davis. After be began to suspect the filmmakers were adding scenes for her without letting him know, he quit. As noted below, many other prominent male stars turned it down before Modine took the part. While it was partially a boon to the producers in that he actually knows how to fence, he was also not the first or even the 17th person you'd think of for an action-adventure swashbuckling male lead at the time.
Due to the casting distractions, Harlin hadn't really been able to pay attention to the sets and production design. When he finally did, he didn't like any of it. It all had to be redesigned and rebuilt in a rather short time frame—and then the script had to be rewritten to accommodate the changes. Both had a lot to do with driving the film's budget way up.
Oliver Reed had been cast in a minor role but had to be replaced after (surprise!) he got drunk and flashed Davis on the set.
Meryl Streep was also very, very close to playing the part of Morgan but had too much of a busy schedule to work it in.
The origins of this movie actually date back to 1986 when a movie called Bloody Bess was in production. The movie also starred a female swashbuckler, but was set to be a lot more violent and darker than Cutthroat was. The movie was cancelled but Renny Harlin, who was working at Empire Studios at the time the film was in talks, liked the idea of a female pirate and reused it later on.