Just how important is the +1 button as a signal for the Google algorithm? Well, we don’t know yet. But it’s pretty clear that Google wants it to be important. And perhaps because it’s a lot harder for spammers to abuse – yet. Because you can buy/rig back links. But, getting individuals logged in to their Google Plus accounts to +1 your page? That’s a lot harder to automate. And you can bet that, just as a link from a highly authoritative website means more, getting a +1 from Robert Scoble means more, too. Perhaps that’s the very point? Perhaps it really is the best way for Google to confirm great content. Although, content can be great without someone +1’ing it, can’t it? In fact, I think I’ve only +1ed sites precisely because I want them to rank high. Friends sites. My sites.
A site can be awesome and have great content without you wanting to share it with your friends – especially if it’s business related.
Of course, Google is stressing that Webmasters not put too much emphasis in any one signal and that “there are more than 200 signals that we use to determine the rank of a website.”