Facebook first-quarter revenue up 38 percent

Facebook Inc's first-quarter revenue increased 38 percent year-on-year, as the world's largest social network continued to grow its mobile advertising business.

Shares of Facebook were down 43 cents at $27 in after-hours trading on Wednesday.

Facebook said it earned $219 million, or 9 cents a share, in the first three months of the year, compared to $205 million, or 9 cents a share, in the year-ago period.

Excluding certain items, Facebook said it earned 12 cents a share.

Facebook's revenue in the first quarter totaled $1.46 billion, versus $1.06 billion in the year-ago period. The company said that mobile ads accounted for 30 percent of its total advertising revenue in the first quarter, up from 23 percent in the fourth quarter of 2012.