Could Slack's Slackbot herald the era of virtual colleagues?

Flickr co-founder Stewart Butterfield says AI in the workplace 'will be about making us more efficient rather than taking our jobs'

Virtual assistants powered by artificial intelligence are a staple of popular culture, from HAL 9000 in the Space Odyssey series to Samantha in 2013 film Her.

But these assistants are no longer science fiction. There's Apple's Siri, Microsoft's Cortana, Google Now and the recently-unveiled Facebook M. Plus, there's Slackbot, the "assistant, notepad and programmable bot" whose potential is one reason workplace communications startup Slack is valued at $2.8bn by investors.