One advantage of +1 over Like is that it lets you recommend things without appearing to approve of them. When I encounter a blog post headlined "Tickets for Apple's Developer Event Selling for $3,500 on eBay" and click the Facebook "Like" button, it appears on my Wall above the phrase "Mike Elgan Likes this." It makes me look like a sociopath. Google's +1 is more neutral.
Google currently has two incompatible systems. You can click +1 on search. But on Buzz, where the +1 could really find some use, Google uses the word "Like" in a system that's disconnected from the +1 recommendations. This is especially awkward because Google went to great pains to connect Profiles and Buzz. But +1 recommendations show up in Profiles, and "Likes" remain in Buzz. It's a fractured mess. Meanwhile, Facebook's "Like" system is unified.
Why +1 and Like matter
Social recommendation tools like +1 and Like can potentially help users do things such as the following:
• Get and give recommendations to friends (replacing link sharing).
• Bring attention to cool stuff (replacing or enhancing Digg and Reddit).
• Set up popularity polls (replacing poll plug-ins on blogs).
• Engage in social science research (replacing text-based voting on American Idol).
The exciting thing about the Like-button concept is that it can, and probably will, spill over into the real world. Within a few years, you'll probably be able to "Like" TV shows, locations (via existing location-based services like Foursquare, Google Latitude or Facebook Places.
Smartphone app-based services are getting better and better at recognizing songs and TV shows (by the sound), and soon they'll be able to recognize objects that you photograph with the camera in your phone. So you'll be able to "Like" all kinds of content and objects in the real world.
Google's +1 system is new and experimental and therefore isn't changing the world yet. Facebook's "Like" system is becoming influential, but it's still overshadowed by Twitter, link sharing and other ways of sharing and recommending content.
The reason this is a big deal is this: History tells us that obscure, trivial services like Twitter and Facebook and even Google itself can rise to dominate user attention, and make billions for the entrepreneurs who get it right. Whoever dominates "Like"-type services could end up making enormous amounts of money.
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