Ending

i think the point of the ending was to illustrate that Kimberly was not just a one-dimentional sociopathic character. Notice her indifferent facial expressions as she switches channels, pausing at the news bulletin about the kid who shot up his school. I think she self, including the filmmakers', that these two morally bankrupt kids are alike. When she cries at the home video of her and her boyfriend, i think that she 'really loved him' in as much as she is capable, that's why she went through the trouble of conspiring, sleeping around, and lying just to get back at her bestfriend. Remember how she comforts her friend Brittany after her boyfriend dumps her also. She tells her that 'this experience will make her a better actress in the future, simply by remembering back to it. That is what she was doing, i think.

My take is a bit different than the norm. Personally, I think her tears weren't a show of remorse at what she had done, but a memory of how her ex-boyfriend hurt her which in effect caused all of that. Notice how she started off watching herself, switched the channel with an emotionless response, and only when she turned back to herself did her face change. Now one can reasonably conclude that seeing the images on the other stations and then seeing what little it was all for broke her will. However, I find it a bit more than a coincidence that at that moment she saw her character doing the same kind of seductive dance that she was doing for her ex when he hurt her so. Add to that, that just moments before she basically told Brittany that she did what she did not so much for the fame (which was probably more of a bonus in her eyes) but for the revenge. So, her crying simply because she saw how little it was worth doesn't conform with the idea that she did it out of hate (although it's possible losing her best friend also hurt her even though she thought it was a good idea previously).

That said, I'd very much like to believe that she felt something for what she did. We know she feels pain towards the loss of her brother, we know she feels pain towards the distance between her and her father, and we know she feels pain about the situation with her mother, but did those things along with the image of what she got out of it push her to her breaking point or are they simply factors that not only led to the issue with her ex in the first place, but the whole episode as well? In the end though I can't really decide what to make of her. She tells Brittany that she never wanted to be Anne Frank and that it was just a set up, but we already learned that what she told Anderson about ger brother giving her the book (thus why it was so important she play Anne Frank) was actually true. So, was she then also lying that the whole thing was to get revenge with being famous only a secondary issue? I don't know, it could go either way for me, but one thing I'm sure about is that she's mentally disturbed and prone to acts of irrational behavior is far from consistent with past actions. So, the ending is up for serious debate and can be taken many ways - I happen to like that better than any other possible ending.