How important is social media to your goals? Well, I guess that depends a lot on what your exact goals are. If you want a lot of people to see your movie or visit your personal filmmaker website, than social media is the key to getting people there.
There are search engine marketing firms that have a good grasp on social networking and how it relates to media and getting the word out about your product (is your movie on DVD? online video? merchandise to promote your movie, etc). If you can get enough followers on Twitter, or enough “likes” on Facebook, then people will see your page. They will follow your words. And ultimately, they will see your movie. The first step is signing up for all of the social networking websites. Don’t limit yourself to just one. Take small steps and go from there.