A lot of people in Silicon Valley think that chat bots are going to be the next big change in how we use our phones. These simple programs will live inside chat apps like Facebook Messenger and send messages to you as if they were human.

Think Siri but embedded everywhere — and not just using your voice, but also text and other ways of communicating.

Evernote's cofounder, Phil Libin, called them the best thing he's seen since the iPhone. Microsoft just released a teen version of a chat bot that talks only like a 14-year-old.

But these chat bots are also job killers.

Msg.ai is a young startup that's working to connect big brands like Sony with customers through messaging. Presenting at Y Combinator's Demo Day, its founder, Puneet Mehta, touted that Sony Pictures replaced 70 human operators with one AI chat bot.

And that's just one company.

Others, like Disney, have been playing around with chat bots as a way to reach fans of shows and movies.

Without bots, it would have been hard for Disney to let Facebook users chat with a Miss Piggy character. Rather than staffing employees around the clock, it's easier to program a bot to have a personality and push people toward ticket orders.

That doesn't mean customer-service jobs will be totally obliterated, though. Msg.ai does hand off customer-support requests if they get too tricky for the AI, and a human agent can step in to answer the question. But the number of those is already diminishing — 70 humans to one AI bot in Sony's case — and won't slow down from here.