They would split the exchange side of their ad business from platform side, which is Google.

That's the whole reason they are being sued because they run both sides of the ad marketplace.

Google's business would be the same. Sell ad space.

To add to that, the exchange is specifically for the display network, so websites and app that aren't Google properties.

This part of Google, while still worth a couple billions in revenue, is an increasingly smaller part of the whole.

But if google makes this change, it will likely follow that other (more self-referential) companies might also follow.

Funnelling customers to Alphabet's advertisers.

I was going to say, isn't 90 percent(ish) of Google's revenue advertising and 80 percent(ish) of that search advertising? What is Google's business if not to sell ads?

Collecting and selling user data is a business.

License some kind of IP to Alphabet for a rate that happens to be exactly what their operating expenses are?