A site uses captcha because it is threatened by automated use. A site uses Google's CAPTCHA because the site cannot afford to build a (effective) CAPTCHA. If Google required the site to pay to use their CAPTCHA, those costs would be passed in some way to the user.

In other words, if Google's service didn't exist, you'd be experiencing less of the site, or no site at all if they chose to use a paywall that you refuse to pay for.

I am not saying that the service is not useful. It certainly is . What I am arguing is that it requires the users to do some amount of work and so it is not free for them, and I am of the opinion that Google benefit from it much more than I do.

Anyway, I am not completely against it, as I said above depending on the situation I make use of it.

It's the usual comparative-advantage thing, though. Five seconds of your brain reading something is essentially worthless to you (unless someone is paying you to read this comment), but of value to Google. The resource behind the CAPTCHA is of minimal value to Google (what are they going to do with an account at startup-of-the-month), but of more value to you. The transaction is mutually beneficial.

The value Google gets from the thing they want, and the value you get from the thing you want, aren't particularly comparable.

The alternative would be you're doing different work (i.e. more intellectually demanding) on each different site as they invent their own CAPTCHA, and rather than benefitting anybody, it would just be an annoyance between you and the content you want to reach.

IMO, this is strictly better.

Taxes work the same way. You pay money (or, if you wish, you work for money you don't get to keep) but don't get money in return. Rather, the money goes toward societal improvements. You can debate whether they're societal improvements you personally care about, but it's not a very interesting debate, because societal benefits aren't meant to be uniformly attractive to everyone.

Except, everything funded by my taxes has to be open, freely accessible, etc.

Google is using ReCaptcha as measure to get an unfair edge over competitors and make competing even more impossible.

> Except, everything funded by my taxes has to be open, freely accessible, etc.

You must not be living in the U.S. Even as strong as the FOIA and public records laws are, there's a huge amount of information and records that are exempted from free access:

http://www.rcfp.org/browse-media-law-resources/digital-journ...