Chick flicks have been around as long as movies. They used to be referred to as "women's pictures".
Typically movies targeting women deal with love and romance and have a happy ending. They have at least one strong female lead and the story generally deals with a couple or couples overcoming relationship struggles. Love triumphs in the end.
The Twilight movies qualify and were a massive box office success. Women will pay for something that resonates with them. Statistics show that 75% of the opening day crowd at Twilight were women.
Remarkably, I have been awake past 10 pm the past two evenings and thus have been able to enjoy The Proposal the first night and Couples Retreat the second. Both are mushy movies and both I thoroughly enjoyed.