While sharing its financial results for its fourth quarter, Twitter today announced a number of new milestones that showed the service’s user growth has slowed while its mobile advertising share has grown. The social network has now passed 241 million monthly active users, 184 million of which were monthly active mobile users as well.

The company also revealed that it generated $242.7 million in revenues, $220 million of which came from advertising. Of the latter, a whopping three-quarters came from mobile.

Here are the numbers as they appeared in the release:

  • Average Monthly Active Users (MAUs) were 241 million as of December, 31, 2013, an increase of 30% year-over-year.
  • Mobile MAUs reached 184 million in the fourth quarter of 2013, an increase of 37% year-over-year, representing 76% of total MAUs.
  • Timeline views reached 148 billion in the fourth quarter of 2013, an increase of 26% year-over-year.
  • Advertising revenue totaled $220 million, an increase of 121% year-over-year.
  • Mobile advertising revenue was more than 75% of total advertising revenue.
  • Data licensing and other revenue totaled $23 million, an increase of 80% year-over-year.

When Twitter’s IPO filing was made made public in October, the company revealed it had 215 million monthly active users, 100 million daily active users, and was seeing 500 million tweets per day. Those were round numbers, and the company only offered an exact figure for the first metric: 218.3 million average monthly active users in the three months ended June 30, 2013.

During the same time period, Twitter found 75 percent of that number accessed the service from a mobile device (phone or tablet), or about 163.5 million monthly active mobile users. According to the numbers released today, that percentage is now at 76.3. As you can see in the chart above, user growth is slowing, as is the growth for the percentage of mobile users.

Twitter also said at the time that over 65 percent of the company’s advertising revenue was generated from mobile devices, and that it expected that proportion to grow “in the near term.” Indeed it has: 75 percent is nothing to balk at.

Like Facebook, Twitter has shown it can make money from mobile, even though its user growth has started to slow. The difference is that Facebook makes a lot more money, and the fraction of its users going mobile continues to grow.

This was a decent quarter for Twitter, but there’s still a long road ahead as a public company. Investors want to see long-term potential, and if the social network doesn’t figure out a way to stop the slowing of its user growth, it will have a very hard time.

Top Image Credit: Scott Beale/Laughing Squid