From a slightly different perspective than the previous (very awesome) posting, as readers we need to ask ourselves whether Nora actually DID transform any social tradition or did she merely transform herself.
Based on the story, there is indeed an element of feminism and self determination, and a characteristic of nurturing that is unique to women. There is also this inner need to be needed, the want to be admired, and the hopes to be appreciated. All of these were the social traditions of women at the time of Nora's tale, and the LACK thereof where the social traditions of males.
When she finally got the ultimate smack in the face with Torvald's obvious lack of care, appreciation, and substance, Nora simply fell numb out of shock, tiredsomeness, and sadness. She, however, did not try to place her private battles to set an example for anyone else. She simply did it for herself: For once, and for the first time ever, she did it for herself.
Therefore, it is hard for me to see how she individually transformed social tradition when, in fact, it was the social traditionalism what betrayed her and ultimately led her to change herself.
Your question is very insightful as it picks up a key theme in this play. In A Doll's House, the position of females in Ibsen's time is examined and he presents his hope for feminism and equality through the character of Nora and her realisation of her situation and her choice to embark on a search for her own identity. Thus in this play the notion of the individual is very closely linked to the wider background of gender struggles and the ability of women to determine their own lives.
At the beginning of the play, the relationship of Nora and Torvald is examined. It is clear that their relationship has more in common with a father and daughter relationship than with a husband and wife, and we discover that Nora relates to her husband and is treated exactly the same way that she related and was treated by her father. In response to her husband's insulting comments and patronising remarks, Nora cajoles, begs and acts like a child (or even a "doll"). Torvald even says: "Has my little sweet tooth been indulging herself in town today by any chance?" Nora responds using childish phrases: "Oh. Pooh!" It is clear that Torvald possesses Nora and regards her as nothing more than a belonging to make him look good.
Nora, too, at the beginning of the play, is caught up in this "Doll's House", as we can see in her definition of freedom which she gives to Mrs. Linde: "Free. To free, absolutely free. To spend time playing with the children. To have a clean, beautiful house, the way Torvald likes it." She is unable to perceive her situation as being caged inside her "Doll's House" and plays a part of the perfect wife according to her husband's wishes.
Of course, the action of the play, and in particular the realisation of Torvald that Nora has deceived him and his response, triggers the epiphany that Nora needs to realise the truth of her situation and give her the desire to escape this "Doll's House". In his response to this realisation, Torvald shows himself to Nora for who he really is: a self-centred, petty man who is concerned only about keeping up the facade of marriage: "From now on, forget happiness. Now it is just about saving the remains, the wreckage, the appearance." It is this unmasking that gives Nora self-understanding of her situation. She says to Torvald, "I've been performing tricks for you Torvald. That's how I've survived. You wanted it like that. You and Papa have done me a great wrong. It's because of you I've made nothing of my life." By the end of the play then, she becomes a stronger, tougher more independent individual, determined to make her own life free from the constricting gender roles that have been imposed upon her. She has shown that she is able to challenge wider institutional structures such as the place of women, and to do so with success.