Why is Harry Potter and Twilight so popular?

They are popular because they are about teens. The casts also are famous. The story also is unique. It's beyond ones imagination. Most of teenagers these days are interested of that kind of stories--witchcrafts and vampires. It's also not boring. It has actions, a little bit comedy, drama, and about young love (all for one!).

It's a person's nature to try comparing 2 different things. I admit that there are lots of things to compare from both movies. Especially the fans of both movies who were the most people likely to compare them.

I'm going to ignore Twilight because it can't really be compared. Other answerers have already given adequate answers. I searched the internet for a keyword search on "why are the harry potter books so popular", to find some more academic presentations. However these yahoo answers are sometimes interesting - though seldom academic! I noticed that most of the other questions relating to the subject "why are the harry potter books so popular" have already been answered so I thought it pertinent to write something here, in case I managed to spark someone's interest into a quest of knowledge which for some reason seems inaccessible to the majority even in this age of information, few people have been initiated into (or initiated themselves) the esoteric side of human life. Sometimes this can be called 'occult' (means 'hidden' or 'obscured') and also is related to mysticism, hermeticism, and alchemy (NOT about turning metal to gold which is widely recognised by anyone who's read an article about alchemy and its allegorical - not mystical - records and writings. The reader may wish to refer to the definitions of such words mentioned above, especially the word esoteric and its antonym exoteric. The majority live in the world of the esoteric whilst the exoteric, the hidden world which exists throughout the history of natural philosophy, mythology, religion, psychology and magic (read: science) requires a potentially enormous quantity of knowledge or practical experience - most importantly conditioning or education into the techniques and the wisdom or intelligence (read: true information). As one can imagine this kind of gnosis (also check out this word which means 'knowing' and is related to knowledge of spiritual mysteries - according to some scholars is what is represented by the 'G' on the compass and square of the fraternity of free and accepted masons) - this gnosis has been passed down within particular initiated societies often deliberately secreted - kept secret - in order to protect its initiates and practitioners from enormous persecution by the rabidly superstitious often religious orders. I've no idea why myself since I'm fairly new to this historiography of the occult, however there is another reason to keep such magical practices secret - that is that it's simply impossible to distribute such specialist knowledge on a wide scale. This is why the 'mass' the majority today have nearly no idea what has actually happened in history - it's impossible to distribute such grey area details on a mass scale, so instead reality is simplified and reduced to information which may be widely disseminated and accepted - and essentially the bits which don't fit with the ideals of the ruling class at the time are omitted. Yes this occurs today as much as it did hundreds of years ago, thousands of years ago even though potentially everybody can discover a much higher reality since there is so much of the real information in the public domain today - however there is not the time nor the inclination nor the understanding that this process can take place at all. There is also today the appearance of a viable collective reality even though we get clues through the cracks very few people are able to question it and think that it's natural that all the convictions they have - which is most of them - are made for them. It's much easier this way -and besides, the truth isn't always nice, it's more fun simply to confront ones own immediate situation and have fun. Furthermore, life would not be as FUN if we all understood everything. Mystery and mythology is an essential requirement for humanity - which brings us back to the narrative of Harry Potter. The reason it is so popular is that for the first time Rowling has brought a flawed, but compelling package together which re-introduces many archetypes which have had such enormous impact on the development of our cultures, language, science, mythology, religion, technology - on our history - that few people understand or even are AWARE about but that they REQUIRE on a fundamental level as they are part of our collective legacy as enormously aware and intelligent sentient beings. Consequently people have simply lapped up this less than profound narrative (which alludes to extra-profound intelligence from history of symbolism and astrology, as an example) and some readers will be searching for more! I'm guessing that the majority will not be inspired to investigate, their interests may lie elsewhere. Of course then there is the story-telling, the characters to identify with and the scenarios which make us support them absolutely. You may want to read something about the archetypes of storytelling, I won't take time to list them here - I once read a 700 page treatise by an author called Christopher Booker ("The 7 basic Plots"). If the reader is requiring references except the few bits of vocab I can remember in this unstructured answer, I was in the Atlantis bookshop here in centra

Twilight is only popular wil tween girls. there is no substance, they are incredibly easy reads for people who an't handle real vampires.

harry potter can be enjoyed by all ages. there is someone in the books that everyone can relate to. the story is also relatable

I think that they are popular because many girls and guys like the romance (more in Twilight), the action, and the fantasy.

because they are huge franchise films.

fans just love the books/movies.

people like different things.

you may not be crazy about the films but other people are.

its just the way it is.