Can it help you find an audience for your movies? Sure!
I have a twitter account: janekk, and from the first day I started it, I had followers. After a couple of months, I only have a couple hundred followers but it grows every single day. I probably average two to five new followers a day and they vary from all over the world and across many industries (not just film).
I find twitter to be a great networking arena as well. I have already met a number of people in the film industry through twitter. And I am following and, in turn, being followed by major indie film players to whom I've never had major access prior. In fact, without my twitter account, I probably would never have interacted with half of my followers.
I tweet (things I write about on twitter) to my tweeps (the people who follow me on twitter) about the film industry. I may tweet about something I wrote on my blog or feature an article I find useful to filmmaking.
And as I tweet about filmmaking, I do plan to tweet about the films I am making. And those tweets will be seen by my tweeps who will hopefully check out my film and mention it to others. They may even tweet about it to their tweeps! And that tweeter may have thousands of followers!
As we know, word of mouth is essential for any film's success. One more person talking about my film could translate to a number of new audience members. He tells one friend who tells a friend who tells a friend and so on and so on.
But isn't twitter full of nonsense? Sure there are tons of people talking about every move they make and that can get a bit annoying. But you take the good with the bad and just ignore or laugh at the silliness.
Will only a couple hundred followers really help? It can't hurt. It may not make all your money back but it's a relatively easy and accessible way for you to take control over your publicity of your film. We need every tool we can find to get our films noticed.
So start your twitter account and get talking. You never know who you'll reach and every new person who knows about your film is one more member of your audience. So why not twitter your way to a larger audience?