What is paranormal romance?
Well we can easily define paranormal romance as subgenre of romance. But what is it really? Paranormal romance combines the supernatural world with that of the real, the natural, the plain. One lover is sure to be something special and the other lover is special because they are so plain; something is found in their ordinariness that strikes a cord with the extraordinary lover.
More than not these stories take place in America, especially when dealing with vampires, but it's not a requirement for the genre. Paranormal romance usually blends mystery, thriller, or suspense as part and parcel of its tale. You could consider these novels to be more than a bit Gothic in theme. Anita Blake Vampire Hunter and the Twilight Saga are two such series that can be found within the category of paranormal romance.
Why do people like it so much?
The sales of paranormal romance have risen over the years. It is not uncommon to find several titles of paranormal fiction in romance aisles. Why is that? As I said when discussing Edward and Bella in the Twilight books, I believe it is because we are all craving that extraordinary romance.
As with time travel romances, paranormal romances that involve vampires have that glorious advantage of a love out of time. One person waits, separate from the time stream of the normal world with all its stresses and hectic schedules just for you. Waters run deep in the one that has been waiting, he (or she) knows just what it is like to live a small eternity in loneliness and now that you've been found, you won't be let go. He (or she) will love you forever.
Besides vampires what fits into this category?
Magic users, lycanthropes (like werewolves), selkies, fairies, ghosts, superhuman capabilities (like flying), gods and goddesses, and angels and demons are all perfectly acceptable.
If you have more on the subject of paranormal romance feel free to add!