Here's why you need a website. In this age of social media, when a person wants something, the first place they check is the web. The storyteller's URL is their face to the world and their business card. If you are going to put your best foot forward to a perspective employer, this is the place to do it. The small addition of your URL to every twitter profile, blog or business card, is an invitation for someone to find out more about you.
What goes on your website? People will want to know the type of stories you tell and what the performance will cost them. Will you do workshops? They want to see what people have been saying about your performances and if you have cds for sale. Share where you have been telling, where you are now and where your travels will take you in the future: you may be coming to their neighbourhood....A podcast story or two could also be an asset. An "About Me" section will also tell them a bit more about the artist behind the stories. There may be more, but at the very least a contact form/email address and links to Facebook and Twitter will round off the site.
Facebook and Twitter are necessary, but will not replace a good website. Through them you can interact directly with your fans and raise the awareness of your work. Often, they become a record of the comments, perceptions thoughts and opinions of others, rather than the messages that you may want to communicate.
Keep your website up to date and link to lots of other storytelling sites. Encourage others to link to you. The search engines will notice your efforts and give you top results. When someone is looking on Google for a storyteller, they will find the one with a good website.