Lovesgliders said it well. Imprinting is not something to try lightly. An imprinted duck is a lifetime commitment, and requires a great deal of sacrifice. And if at some point you're not willing to make the sacrifice, it will be the duck who does.
Ducks are intensely social creatures. They must be with others of their own kind 24 hours a day, 7 days a week. An alone duck (even for five minutes) is a lonely and scared duck. Often they will simply pine to death from loneliness. An imprinted duck will never realize it is a duck, and so people must take the place of its flock. This means that you must be ready to bring it indoors (and change its diapers every three to four hours, rinsing & washing duck poop diapers every single day), and be home with it all day every day. And no one else is going to want your imprinted duck, so if you ever move somewhere, you'll have to be sure you can have pets there.
Before doing research on imprinting, make sure you know everything there is to know about duck care. Read Holderread's book, Storey's Guide to Raising Ducks, and talk to some of the folks on this board who have indoor ducks (nettie comes to mind). And keep in mind that you don't have to imprint a duck in order for it to want to be around you and to be a good pet.