Can Twitter solve its user problem?

Twitter reported a net loss of $125m (£82m) in the fourth-quarter, beating analysts' expectations.

However, growth from the last quarter was significantly slower. The site managed to add only four million users in the past three months.

The company's chief executive has warned that bullying on the service is driving users away.

The BBC's Samira Hussain asks what Twitter will need to do to ensure it continues to please investors... and attract users to its microblogging service.