It’s pretty easy to enable +1 Button. Open a browser and sign into your Google account. Then search for Google Experimental or just type in the following URL http://www.google.com/experimental/. You will see “+1 button”. Click 'Join this experiment'.
Now navigate to http://www.google.com and search for any item. You should be seeing a +1 button next to the search result. This button will not be enabled for http://www.google.co.in.
Initially I thought it’s Google version of Facebook “Like” button. But after trying it out I felt it sucks! Big Time! I search for some stuff and get the Google results page. How could I rate the result with my “+1” without actually going through it? Also the preview of the search result (another feature which Google introduced recently) doesn’t empower me to do so. So if I am actually interested in marking a result “+1” then I have to open one of the result, read it and then religiously go back to the Search Result page and Click “+1”. Probably after doing this I will feel I am a respected user of Google :) . On the positive side of “+1”, Facebook “Like” button reflects my mood rather than promoting a genuine content. So Google “+1” is of more value to me than a Facebook “Like” button.
To me it’s a poor usability if not a poor product idea. Simple reason being overhead on user to mark a genuine result “+1” and most of the time I wouldn’t want to do that because it isn’t inline with my regular flow of using Google Search. As a user I would have liked the “+1” button on the result page which I was reading or some browser extension like stuff.
Anyways it’s still in experimenting phase, let’s see how it comes up.