'Mobile shift is happening,' Facebook execs say

Facebook reported better-than-expected results across the board Wednesday, with 76 percent year-over-year ad growth in the fourth quarter.

Ahead of the company's earnings call I caught up with COO Sheryl Sandberg and CFO David Ebersman about what's driving the growth.

"This is obviously a really exciting quarter for Facebook ... the mobile shift is happening and products are working for marketers," Sandberg said in a phone call.