Google has been wanting to place it's flag in the social network land for a little while now and currently the internal codename for their upcoming social project is "Emerald Sea".
But, that name could now be old and replaced by "Google +1" or "Google Plus One". It's unknown if it'll be one or the other but right now it is a decision between both of those names. The +1 comes from the same mind set of Facebook's Like and Twitters Retweet.
Another source says that a possible candidate name is "@Google" or "At Google" - but even though people have been using this as a @reply to someone, it would most likely enrage the Twitter community.
In it's current state "Google +1" is said to be a toolbar that will appear of most of Google's services. This should also include their Chrome browser - although one source has said it could be an extension, rather than fully built into the browser - at least for the time being.