It's like WHMS because of the fact:
A) They are right for each other, only it takes them years to figure it out.
B) Most of the film deals with semi-serious relationship and career issues just like WHMS did.
C) The whole tone of the movie is about a chance encounter and hooking up with the one you're supposed to be with, but don't (won't) realize it for quite some time and during that time there is the possibility that the two main characters may have changed, fallen "out of love" just like WHMS.
This isn't reaching for comparisons. Even the producers said it was supposed to be a WMHS for Generation Y... Which again, imo, is why it really didn't do much for me because it was too unfocused in a lot of parts.
Also, what got this movie made:
[sp]The scene when Oliver goes to Emily's mother's grave and describes it to her over the phone. Every film has one stand-out moment that basically let's the producers spend millions just to film this "one" scene even if the rest of the movie is rubbish.[/sp]