As I reported at Search Engine Land as Google Operating System noticed, the Google +1 button in the search results is by default now hidden until you place hour mouse cursor over the search result.
When you mouse over the search result, the +1 button appears.
I now see this, but not everyone sees it yet. It seems to be a test Google is trying out or maybe something they are rolling out.
Here is an animated gif of the mouse over affect.

Then when you click on the +1 button, it will highlight blue.
As I mentioned, I like this - it declutters the user interface and makes things a lot cleaner for the searcher.
Forum discussion at WebmasterWorld.

Comments:
Nick Stamoulis
12/13/2011 02:52 pm
It's an interesting move on Google's part. You'd think that they would want this little reminder of Google+ wherever they could possibly show it. I'm not convinced that they majority of searchers even know what the +1 button is yet, so hiding it like this doesn't quite make sense.
Christie Mayer
12/13/2011 04:21 pm
I think it's a good decision. It's definitely cleaner and I suspect it will still draw attention as now there is movement on the screen as you mouse over.
Jerry Nordstrom
12/13/2011 04:56 pm
I agree with Nick. The majority of my clients do not know what G+ is, and even when we explain it they are not certain how it works or aids them. Trying is the best way to do this.
Search Engine Optimization
12/13/2011 05:24 pm
It's nice to "declutter" the results page - Google doing another positive for the user (as subtle as it is) - Proves that they are not jamming Social Search engine idea sown users throats.
Rxbbx
12/13/2011 06:10 pm
This is a good thing... they should wait with such things till Google+ is big enough and standard. People are now playing with that button to get good results...
Internet Marketing Company
12/14/2011 01:02 pm
Highly agree with you that many of unaware by the +1 button. And can not understand the intention of google for made this change!
pramod srivastava
12/15/2011 07:56 am
I agree with you. you are write.....