Shares in Twitter have fallen by some 11% after it posted disappointing engagement figures. The social network says "timeline views per user" dropped by 7% globally in the third quarter.

Twitter says its fourth quarter revenue may miss its targets set by Wall Street.

While analysts fear more mobile users are turning to messaging services like WhatsApp and SnapChat.

But it was both the number of new users and how often people refresh their timeline that disappointed.

Twitter had 284 million users at the end of September, up 13 million from 2013. That means it has just under quarter of the number of users that Facebook has.

And it was well below the user number most stock market analysts had expected.

The rate of increase in how often users refresh their timelines also failed to impress - it rose 14% year on year to 181 billion views - but the quarterly rise was much smaller than expected.

However the company said revenues more than doubled to US$361m (€284m) in the three months to end of September - and it posted a profit of almost US$7m from a loss of US$17m a year earlier.

"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," Twitter CEO Dick Costolo said in a statement.

Newstalk's business editor Ian Guider says Twitter is not making in-roads into the market lead held by Facebook.