The words strike terror in any entrepreneur's heart: "Hey, did you hear that Google is getting into your industry?"

We've seen it a few times recently, after Google announced a plan to attack the $140 billion video game industry, and then rolled out privacy changes that some say are designed to cement its mammoth lead in the $129 billion digital advertising industry

Now, Google is placing a bet on potentially the biggest business yet, one that the U.N. World Tourism Organization estimates could be worth a total of $830 billion, in just one segment of the industry.

Drum roll please: It's the travel and hospitality industry.

$100 billion already

The announcement came this week, in a blog post by Google's Richard Holden, vice president of product management for travel. 

It was easy to miss the importance--because of course, Google is already in the travel industry, and it's been slowly and without much fanfare launching feature after feature.

In fact, a couple of years ago an outside analysis suggested travel accounted for about 15 percent of Google's overall revenue, and that its pieces would be worth $100 billion as a standalone business--more than competitors like Priceline at the time.

But as Holden laid out in his blog post, Google has now been consolidating many of its various travel offerings together into a single interface, and it's considerably more than just the sum of its parts.

It's all called Trips, same as the travel app that Google first introduced almost three years ago, and it's a pretty intuitive way to organize all of your research and reservations for any one trip in a single place, accessible on any device.

"Things to do"

It's probably easier just to walk through a few examples of how Google Trips works, instead of trying to explain all of this in the abstract.

So take for example, a short trip my family and I plan to take at the beach in Delaware once school lets out. 

Just entering the location in the search field at brought up a "travel guide," a "things to do" section, and a "plan a trip" option. These were pretty robust; within a few seconds I'd already hit on a few good ideas for where my wife and I could take our daughter on the trip.

I'd already done about two hours of research and chose a hotel to stay at before doing this little experiment. Lo and behold, the hotel I'd picked was the first one Google recommended.

I suspect, of course, that Google was either making this recommendation after a) looking at my search history, b) aggregating my browsing history, or c) digging through my Gmail account, where I already had been communicating with the hotel.

"Kind of creepy"

About that part: As the New York Times put it while reviewing the mobile app version of this when it first appeared: "It's kind of creepy."

But in my case, there were also some times when it seemed like our overlords at Google were a little less omniscient.

For example, the "plan a trip" option by default suggested my family should fly from New York City to Baltimore or Philadelphia--and then, rent a car to go the rest of the way to Delaware, I guess?

Short version: That's pretty silly. You'd be much better off just driving the whole way--rather than paying $260 round trip per person on Spirit, as Google suggested.

In fairness, it was more useful for a hypothetical trip to Paris, with a clean display laying out some slightly obvious "things to do," like see the Eiffel Tower and the Louvre--although it did also suggest an outdated, pre-fire photo of the Cathédrale Notre-Dame de Paris.

The big advantages

Beyond that, however, the logistics of actually getting to Paris and staying there were pretty slick: laying out flights, times, prices, and hotels, with prices on a single interface. 

And that really seems like the future here. Google brings a few key competitive advantages to this whole thing, including the sheer number of Google visitors, the panoply of services we're already using that Google can string together, and an almost unlimited timeline.

Google isn't even monetizing this the way it probably could; for example, if you want to book a plane ticket, Google sends you to the airline's website rather than selling direct itself. 

At the end of the day, this is potentially an enormous market. That U.N. report estimates international tourism alone amounts to $830 billion a year, and that doesn't even count domestic travel and business travel.

And all of the things Google is doing here feel only like the start of a real focus on travel, not the end result. All things considered, I wouldn't bet against Google getting an even bigger share.