I am sitting here at Facebook’s marketing conference in New York City’s Natural History Museum (TechCrunch has a liveblog here), and the big message Facebook is trying to communicate to the brand advertisers assembled here is that they shouldn’t think about Facebook as a place to show people ads, but rather to tell them stories. Facebook is a “storytelling platform,” says VP of product Chris Cox. Facebook marketing director Mike Hoefflinger put it more bluntly: “We are evolving from ads to stories.”

Just as Facebook users now all have their new, more visual Timeline, brand pages will also soon adopt the Timeline design. Brands will love this because it will give them a much richer canvas to market to Facebook users, including features such as pinned posts and new ad types such as offers.

With pinned posts, Facebook is following in the footsteps of Twitter, which introduced a similar concept on its brand pages in December. But Facebook goes way beyond what Twitter is doing. For one thing, it will now be selling ads in your news feed itself, not just along the side. Twitter for the most part has resisted cluttering the main user streams with ads, (although Promoted Tweets can appear there under some circumstances). Facebook ads will continue to appear in the top right of your Facebook page, but they will also appear in your feed itself, on mobile, and as well as in the logout screen (37 million people a day log out of Facebook, so that is valuable real estate)

But remember, these are not “ads.” They are “stories.” And brands are encouraged to use these stories to create one-on-one relationships with consumers. Usually these stories take the form of things people would like to share like videos of sponsored athletes (something which Red Bull does). A successful ad on Facebook is one that people want to talk about, and thus share on Facebook with their friends.

So how will Facebook make increase the chances that those brand stories will be shared? Probably the most important announcement today for brand marketers is a new Facebook ad targeting product it announced today called Reach Generator. The most likely people who will share a brand’s message are consumers who are already Facebook fans of that brand. Reach Generator is simply a way to target Facebook ads, or “stories” to those fans in different places on Facebook (in their news feed, on their homepage, on their mobile devices, at logout). Ben & Jerry’s, a beta advertisers, found that marketing to fans doubled their engagement rates, and Facebook says other advertisers are finding similar results.

Targeted advertising up until now involved guessing which consumers across the Web would be most likely to be interested in a marketing message. Facebook’s twist on targeted advertising is to show ads to people who have voluntarily stated their affinity to a brand. And those fans then spread those ads to their friends, but only if they don’t seem like ads. So brands need to tell stories.

It’s a return to Advertising 101. The best commercials on TV are mini-narratives. The best magazine ads look like art photos. The best ads online spark a conversation.