Facebook began a slow rollout of ads to the news feed today, but the units are not called Sponsored Stories – as some anticipated. Instead, according to the Palo Alto, CA-based digital giant, they are labeled “Featured” to distinguish them from earned media messaging that users sometimes see.

Annie Ta, Facebook spokesperson, explained the terminology in an email to ClickZ News late Tuesday. “Since people can see marketing messages from both Pages they have and have not Liked elsewhere on Facebook, we want to make it clear that marketers can only pay for stories to be featured in your News Feed if you have explicitly liked the Page,” Ta said. “And because you are always connected to your friends, we are also labeling stories from your friends that have been paid to be featured in your News Feed as ‘featured’ to keep things consistent.”

Facebook initially revealed it would push paid ads to news feeds on Dec. 20.