Twitter gained a net total of only four million new users in Q4 — well below its usual run rate — but came through strongly with both revenue and earnings in the final three months of 2014.

In recent quarters, the company has added 13 million (Q3, 2014), 16 million (Q2 2014) and 14 million (Q1 2014) monthly active users (MAUs). It now has a total of 288 million MAUs.

CEO Dick Costolo (pictured) pointed the finger of blame for the disappointing MAU stat at Apple and, in particular, its iOS8 upgrade, as well as seasonality.

The company was more upbeat on earnings and revenue, where it beat expectations. Q4 revenue nearly doubled to $479 million from the same period in 2013. And the net loss fell to $125 million from $511 million in Q4 2013.

Costolo reassured that new user numbers have already recovered in 2015. Explaining the Q4 letdown he said Twitter lost four million users because of the launch of iOS8.

On a conference call with analysts, he said iOS8 wiped one million Twitter users because they either forgot their password or did not download the app after updating their software.

On a conference call with analysts, Costolo blamed “an unforeseen bug in the release of iOS8” as it related to the Twitter integration for this particular loss.

In addition, a further three million Twitter users were lost after Apple changed a feature called Shared Links in the latest version of the Safari mobile browser in iOS8.

Apple did not comment.

In addition, the fourth quarter is traditionally slower for signing up new users.

Mobile users represent 80 per cent of Twitter’s total MAUs.

Full-year revenue more than doubled to $1.4 billion, while losses narrowed to $577 million from $645 mllion in 2013.

The overwhelming proportion of the company’s revenue comes from advertising (in Q4, it was 90 per cent). And during that quarter, mobile advertising accounted for 88 per cent of all advertising revenue.