As Google's +1 Button gathers more data it will become part of Google search results algorithm but according to me Google +1 will fail drastically when implemented in search algorithm for multiple reasons.
1. +1 requires Google profile
Making a Google Profile a requirement for +1 buttons is a move on Google's part to match Facebook's user profiles. The aim of Google is to have more Google profiles which mean Google has more personal and demographic information about user than it has currently. The motivation for Google is obvious. It needs more user personal data to show more and more related ads to you.
2. +1 May be for SEO Spammers
Google Panda update took a big toll on search engine spammers but with +1 Google will open doors once again for spammer. Google +1 is clearly showing signal that it can give you search ranking benefits where as with Facebook like button, user only recommends the content to their friends. The more motivated user of +1 would be a person intensely interested in search engine ranking.
3. +1 in Google SERP's May be useless
I am not sure if I could ever judge from Google Results (Read Google search result excerpt) the quality of a site or content. If a user doesn't know the quality of a page before a visit, how can they honestly click on +1 for it? In short, Google needs other ways to gather data before they can show recommendation and so they need to convince webmaster's to have the +1 button installed on their site.
4. Google needs Friend Information
Google is focusing more on getting user profiles but for +1 to work on search results page they also need to find people I know i.e. my friends. If I click on +1 it does not make sense to have the same recommendation shown to me again because I anyway know it is good but it makes lot more sense if my friends see my +1. How will Google gather information about people I know can be tricky and I hope it's not using the GMail's address book?
What Google +1 means to you? Share your views in comments below.