Two comments. First, some reviewers are taking the movie too seriously, it is supposed to be a caricature of the 50's. One earlier reviewer cited Sandra Dee and James Dean parallels, etc, no need to repeat it. While it had fun dance music and hits (although I am usually not a Bee Gees fan, even when I was younger) with several famous and soon to be famous actors, the reason I give it a 7 versus something higher is that it gets a little too serious regarding Sandra and Danny (inconsistent with the rest of the movie, even the possible pregnancy is taken less seriously) and it did not keep true to the original musical.
Second, the comments regarding sending bad messages was bit confusing. I don't see this message. One of the earlier reviewers talked about losing virginity as a must based on this movie. Well, to start this is inconsistent with the pregnancy issue where the character is mocked for being "knocked up" and even referred to as trash. The character tries to defend her actions by saying it's better than being an insincere flirt, but you can see she really regrets what she did inside. It also shows how virginity was still the vogue back then and that all the other provocative women were putting on a show. Next there are the comments about Sandy conforming to Danny's (and the T-birds/Pink Ladies) behavior, look etc in order to be accepted. The movies clearly shows that she was accepted before she made the alterations. One of the pink ladies befriends her, and Betty thanks her for her support. Danny letters in track and tries to change HIS LOOK for her in a mutual sign of affection. Sandy is not conforming to Danny as much as it may seem. She is mature in that she is kind to everyone and is responsible. However, she is immature because she lacks confidence in herself and how to deal with Danny. At the end she matures in that department by asserting herself and getting her man. She changes her dress, look and attitude not to conform but to get Danny's attention that she really wants him, and that she is the one in charge, not him. She now is asserting herself, showing confidence and at the same time saying she is willing to accept him for the way he is by "dressing up" for a day. It is interesting though that no one mentioned Danny putting on that awful sweater with the letter on to conform to his image of Sandy. Sandy knew that Danny's jacket, T-bird routine was just a ruse for whom he really was and she figured to play the ruse with him....
Lastly, several commented on the women's roles issue and minorities. It appeared to me that the women had the upper hand in these relationships and a woman was a principal of a school in the 50's, etc. As for minorities and their appearance in the 1950's Rydell was in California. Was there segregation in California? I wasn't aware of any. Secondly, anyone know the percentage of African Americans in a typical LA well to do high school in the 1950's (or the 1990's for that matter)? Let's just say it was really low. So, it was realistic. I do agree that it is not nostalgia for the 50's I feel in this movie, it mocks the 50's. It to me is more nostalgic of the 1970's and the actors who became the stars later on and the music that I heard when I was a kid.