Twitter’s shares tumble on widening loss, disappointing forecast by Tom Huddleston, Jr. @FortuneMagazine October 27, 2014, 5:50 PM EDT E-mail Tweet Facebook Google Plus Linkedin Share icons Twitter’s third-quarter revenue more than doubled to $361 million, thanks to a big jump in ad sales. Here are the key points of Twitter’s third-quarter earnings report. What you need to know: Twitter’s TWTR shares fell more than 8% in after-hours trading on Monday after the company reported financial results more or less in line with Wall Street predictions. While Twitter more than doubled its revenue, the company’s losses widened to $175.5 million from nearly $65 million during the same quarter last year. Twitter lost 29 cents per share, however, compared with losses of 48 cents a share last year. Twitter’s monthly active users grew by about 23% year-over-year to hit 284 million after the company reached 271 million in the second quarter. Mobile users accounted for about 80% of Twitter’s total monthly active users during the quarter, or about 227 million, up from roughly 211 million in the second quarter. Timeline views also improved by 14%, to 181 billion, over the same quarter last year. Twitter CEO Dick Costolo called the third quarter “another very strong financial quarter” in the company’s earnings release. “I’m confident in our ability to build the largest daily audience in the world, over time, by strengthening the core, reducing barriers to consumption and building new apps and services,” he said. The big number: Twitter’s increased monthly active user numbers helped the company post a 109% bump in advertising revenue to $320 million. Mobile ad sales made up the bulk, accounting for 85% of Twitter’s overall ad sales. The company was also able to improve on its second-quarter ad sales figures, when Twitter reported $277 million in total advertising revenue. What you might have missed: Twitter revised its full-year earnings forecast, with the company now expecting 2014 revenues between $1.365 million and $1.375 million after previously predicting sales as high as $1.33 million. Twitter expects sales of at least $440 million in the fourth quarter.