Artificial Intelligence is still a long way from being able to simulate a specific individual, but recreating the limited slice of personality reflected in a Twitter feed is an interesting place to start.

The _LivesOn service is hoping to roll out to a limited number of test users at the end of March.

As with the other services, _LivesOn will require that members choose an executor. At this point, it's as much a thought experiment as an attempt to create a usable tool.

A little bit of immortality

All these companies see the potential for technology to change how people think about death. Goodbye messages can help people left behind through the grieving process, but composing them can also be comforting to people who are uncomfortable with or afraid of death.

"We shy away from death. It reaches us before we approach it," DeadSocial's Norris said. "We're using tech to soften the impact that death has and dehumanize it. It allows us to think about death in a more logical way and detach ourselves from it."

The prospect of artificial intelligence, even in 140-character bursts, can also be comforting to people who see it as a way to live on.

"The afterlife is not a new idea, it's been around for quite a long time with all the different versions of heaven and hell," Lean Mean Fighting Machine's Bedwood said. "To me this isn't any stranger than any one of those. In fact, it might be less strange."