Back in August, fans of digital assistants were pleased to hear that rival AIs Cortana and Alexa were joining forces to improve the overall customer experience. Microsoft and Amazon said the partnership would happen "later this year," but it never did.

As noted by Paul Thurrott, we're now a few days into 2018, and the crossover functionality still hasn't arrived. Strangely, neither company has given a reason why.

When the announcement first arrived last year, CEOs Jeff Bezos and Satya Nadella talked of the mutually beneficial arrangement that would allow the two assistants to access each other's unique skills. Eventually, it's hoped that questions will be automatically sent to whichever assistant can best answer them.

"In my view of the world, because that would be best for the customer, that's probably what eventually happens," said Amazon boss Bezos.

"Ensuring Cortana is available for our customers everywhere and across any device is a key priority for us," added Nadella. Bezos reportedly first suggested the idea of a collaboration at Microsoft's CEO Summit in May 2016.

Integrating the two services would certainly make everything a lot simpler for those who find themselves switching between the two assistants regularly.

While missing the deadline will have disappointed some people, it seems that it won't be long before we can ask Cortana to open Alexa and vice versa. An Amazon spokesperson told Gizmodo: "we're working on it and expect to begin rolling it out soon." Microsoft put out a similar statement, promising it will "have more to share soon."