Audio problem: After Carrie returns from dinner, she is using the computer when suddenly Aiden ("AidenNYC") is shown logging onto her AOL Buddy List (upper right of her computer screen). But for some reason, the show uses an 'IM Chime' sound. When someone logs onto their computer and appears on your Buddy List, it makes a different noise (usually a door-opening sound). The 'IM Chime' sound only happens when someone actually sends you an Instant Message. In this case, Aiden had not IMed Carrie. There was no IM on her screen, and he only appeared on her Buddy List. (00:18:40)
Suggested correction: The sounds for logging on or IM'ing can be changed under the settings.
Because Carrie was brand new to the Internet, she had very little knowledge of how it works. She would not be advanced enough to know about IM settings, or how to change them. (This is clear when she humorously tries to 'hide' from Aiden's IM on screen, thinking he could see her physically). And it isn't likely that she would have changed the settings if she was just starting to use the Internet and had little experience with it. They used the wrong sound on camera.
