Why Advertisers Are Warming to Facebook - WSJ.com

Upwardly mobile

"Facebook didn't have much presence in mobile advertising a year ago, a concern that contributed to the stock-price slide after its initial public offering price. Then, in the latest quarter, mobile accounted for 41% of Facebook's ad sales–and investor attitudes have recovered with Facebook's ad revenue: the shares skyrocketed 30% Thursday.
"Everything worked this quarter," said Brian Wieser, an analyst with Pivotal Research Group."

Why Advertisers Are Warming to Facebook - WSJ.com