After spending the morning at f8, the Facebook developers conference, I’m convinced more than ever that Facebook is about to take over the whole Web. And by the whole Web, I mean, well, all of it.

And if Google isn’t trembling over this, they ought to be. We might look back at this day as the moment when Facebook set itself on a path to eventually dwarf Google in size, power, and eventually, revenues.

Simply put, Facebook is positioning itself to become deeply embedded in almost every single website. And the way it’s structuring this platform, it places Facebook itself at the center of Web more than ever.

Here’s why I think Facebook is about to become a monster.

First, there are the numbers, which are astonishing. Facebook has 400 million users, and that number is increasing at a faster pace than ever.

“If you’re building a website, there’s a good chance that most of your users are on Facebook,” said Zuckerberg. “And if they’re not, they will be soon.”

That might sound like a boast, were it not true. But what really left my jaw on the floor was what Facebook has coming next.

Facebook Connect, announced at the last f8, has been a killer for Facebook, making it the default sign in for millions of websites. Facebook is going to expand on that, creating a kind of super Facebook connect that makes sites more social for users without them actually even needing to sign in.

And by all appearances, these new platforms will be even easier for developers to implement. You can see the details here on the official Facebook blog.But what you’re going to start seeing all around the Web is the “Like” button you’re used to seeing on Facebook. When sites implement Facebook’s “open social graph API,” you will visit a site like CNN.com and see what all your friends “liked” there and you’ll be able to “like” an article as well — without even signing in.

See another example of what this will look like here.

At the same time, Facebook will make it easier for these other sites to access the data of users via the “open social graph API.” That means I’ll be able to go to CNN.com and see a stream of my friends’ activity there, again, without even logging on. It creates what Zuckerberg called an “instantly social” experience everywhere you go.

That “like” gets shared right back to Facebook, which is also creating a better way to search through all of this. And Facebook will now begin pulling in those likes from sites like Yelp, Pandora, and so on. The Web is about to get even more social, and Facebook is placing itself right at the center of this.

There will be some hurdles. I expect this to raise some privacy issues. And Facebook still has the challenge of doing a better job monetizing all of this.

But it’s clear to me that Facebook is on a path to making itself the most essential element of the Web. Sitting here, it’s hard to see how Google, or anyone else, slows down this march toward world wide Web domination.