Facebook reported a big jump in third-quarter earnings, driven by its growing success in capturing a mobile audience. The number of active monthly Facebook users climbed 18 percent overall but spiked 45 percent on mobile devices. Advertising profits jumped 66 percent year over year, with 49 percent of that revenue coming from mobile. It earned $425 million, or 17 cents per share, in the quarter. That’s up from a loss of $59 million, or 2 cents per share, a year earlier. Adjusted earnings were $621 million, or 25 cents per share. That’s 6 cents better than analysts expected.