Career Resurrection: Provided one for Joseph Gordon Levitt. After 3rd Rock from the Sun had ended, he slowly disappeared from acting and eventually took a hiatus. He returned to acting with a few other roles, but this put him back on the map.
Summer was originally envisioned as a blonde to have a more obvious 'summer like' persona.
The studio never intended to include the love documentary in the film - even telling Marc Webb not to film it. This changed when test audiences reacted positively to it. The documentary also originally ran longer - with opinions from Rachel, Summer, Millie and Tom's mother.
The first draft had the film set in San Francisco, rather than Los Angeles.