The site was launched in October 2011 at Brooklyn Beta, a web developer and designers conference.
It was then made available by invitation only until it was made fully available to the public in February.
While the IMDB has a social networking aspect, Buchanan believes this is largely overshadowed because the site functions primarily as a database.
"We wanted to turn that model around and say we're primarily the social side of film watching."
Buchanan says while the site was not conceived for professional reviews, a large number of professional critics have taken an interest in it.
"I think it's very interesting with the usage of it by professional critics because they're paid to write elsewhere, they're not paid to write for our site."
One such critic is American writer Scott Weinberg.
Weinberg says that while there are a number of great websites for movie buffs, Letterboxd has a combination of features that make it unique.
"If you want to group a bunch of films for whatever reason you choose, the site makes it easy and fun to put a gallery together," says Weinberg.
"So you can say: 'Look at all these movies about dragons! I love dragon movies!' That's one of the geeky things that movie nuts do."
Weinberg says that an interactive website for film fanatics can become overwhelmed with "too many bells and whistles".
"I think Letterboxd works because it focuses on only a handful of movie site mechanics and it does those really well."
The site was placed at number 21 in Total Film's future 100 issue, a list that predicted the film industry's biggest movers and shakers in the next 18 months.
Buchanan says the average stay on the site across all visitors is more than eight minutes.
"Which is pretty high considering how short the attention span is of your average internet user."
While there is going to be heavy competition with other social networks and film related sites, Buchanan feels it is wise not to be concerned with what others are doing.
"We know we have a product that people are really enjoying and our twitter feedback has been immensely positive," he says.
"It's too easy to be obsessed by what else is happening, so we'd rather stay focused on what we're doing and always improving our offering. I think if we do those things right then we'll be successful."
-NZ Herald Online