I've noticed that I get the house numbers when I leave 3rd party cookies enabled, and a much harder, often impossible captcha when they're disabled. Since leaving them off doesn't break much else, I do, and just fill out the harder captchas when I come across one. By the way, you only have to fill out the "known" word, the one that's all twisted and usually impossible to read until you refresh the image 10 times. Even completely omitting the 2nd word, which is the unknown word that OCR couldn't figure out, it will still validate.

Am I being paranoid when I think that offering this "free" service is a great way to track people over even more sites and usually the most important conversion pages that don't have the usual google display ads. I don't see a big technological innovation here as it appears that mostly they are checking your cookies to see if they recognize you.

So they can track you better and provided better targeting ads. That's where they get the money from. That's how you pay for visiting websites.

Every "free" service from Google has the end goal of serving you personalized ads. That's their business.

Certainly correct. I guess it is new for me that I'm requiring my users to give their data so they can be served personalized ads.

And there are a number of sites using Analytics, Adwords/Adsense, DFP and a number of other points of connection. They've already offered/bought recaptcha, all this does is make it easier for most people (who have cookies and JS enabled).

I think it also depends on the website? Some offer easy captchas all the time, some not.

One example: I have never seen a "hard" captcha here https://webchat.freenode.net/