Twitter's fiscal 2014 looks promising enough for investors to start buying shares in the microblogging service when they previously knocked it off as a non-profitable venture.

One issue investors brought up was the low user growth in Q4, something Twitter attributes to an iOS 8 bug, losing around 4 million active Twitter users.

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"We said we lost four million monthly active users due to the iOS 8 integration. One million of those monthly active users were Twitter owned and operated monthly active users," said Twitter CFO Anthony Noto. "Three million were on Safari, what we call auto-pulling MAUs, and we lost those. We don't expect to get the three million auto-pulling MAUs in Safari back."

The auto-pulling MAU was out of Twitter's control and due to a technical failure Apple failed to document, Twitter had to scramble to fix the issues Safari users were having.

The actual rate of web browser users on mobile is low compared to the web, where applications are seen as cumbersome compared to web browsers. This means Twitter did not see this as a huge dip in usage.

Twitter co-founder Evan Williams previously suggested the active monthly users on Twitter did not matter, saying "I don't give a shit if Instagram has more active users", following news that Instagram broke 300 million active users. Twitter currently has 284 million users.

The microblogging site managed to hit $479 million revenue, surpassing analyst's projections of $453 million. In after hour trade Twitter's stock hit $45, a 4.9 percent increase.

TagsiOS 8, mobile bugs, microblogging, Dick Costolo