Reverse-engineering the Google +1 button using Firebug
randomistas.tekeu.com
randomistas.tekeu.com
Origin: https://clients6.google.com
Origintoken: APfa0boTRJ3fof-lEyAVjVQzO_sSMz5frFmbeeMTJ2nASXJBVUX7PDb2dnWA3pGrlmuefwvwXuC9l2
Clientdetails: appVersion=5.0%20(Macintosh%3B%20U%3B%20Intel%20Mac%20OS%20X%2010_5_8%3B%20en-
us)%20AppleWebKit%2F533.21.1%20(KHTML%2C%20like%20Gecko)%20Version%2F5.0.5%20Safari%2F533.21
.1&platform=MacIntel&userAgent=Mozilla%2F5.0%20(Macintosh%3B%20U%3B%20Intel%20Mac%20OS%20X%2
010_5_8%3B%20en-us)%20AppleWebKit%2F533.21.1%20(KHTML%2C%20like%20Gecko)%20Version%2F5.0.5%20Safari%2F533.21
.1
X-Javascript-User-Agent: google-api-javascript-client/1.0.0-alpha
X-Origin: https://plusone.google.com
X-Referer: https://plusone.google.com/u/0/_/+1/button?hl=en-US&jsh=h%3Brt%2F225303364-
e72328d15
And in the response he gets there seem to be a bunch of missing fields (on my machine there's the title and information about my logged in Google Account) and there's also the count of +1s on that page. He seems to be getting a 0 return. Wouldn't be much surprise if this is Google's way of showing that it ignored the request.I checked their embed page (http://www.google.com/webmasters/+1/button/) and I don't see that it requires any API key what so ever, so I assume this rpc_key thing is something private to the API and fetched as the button-JS communicates with the server.
These keys are probably issued with limited time validity, so possibly the script of the OP has already stopped working (I haven't tried yet).
We DO need a real API for this though - if we webmasters do Google a favor and add the plus one buttons, the least they could do is give us a means of finding out how many time the button has actually been used.
Otherwise, this is a bit one sided: We lend Google space, we do the work of adding the button, but we get nothing in return.
You get the whole purpose of the button for you in the first place, users encouraged to share your content.
I think they may have thought people might try this. Very cool though.
Most badges or like buttons can be reverse engineered like this, it's not too hard.