Why does people compare Twilight Saga to Harry Potter?

hi really glad that someone started a discussion in my lot which we discuss with our friends daily as a casual talk that why do they do like this , really even i don't understand why they do like this , both have different stories and concept but yeah a bit common in between them that both movies story is taken from novels then converted into movies but that doesn't mean that both are to be compared , really this things surprise me a lot , don't know on what basis they do so , i will be thankful to them if they give me genuine reason behind the comparison.

personally, i dont understand why people compare both, they are total differents, differents stories, the only thing they have in common is teenagers, i think..

Both are very popular movies based on a books for children/teens with supernatural them. Don't hear this comparation often. It's always Harry Potter-Lord of the Rings.