Google Plus One is Google’s own recommendation network: if you are logged in to your Google account, you can “plus one” websites in the Google search results and from the websites themselves. This adds you to a list of people who have recommended that page, which makes up a total count of “plus ones” a page has got. Google then uses this data to help advise your friends (people you are linked to through any social accounts you have connected with your Google account) on what they are searching for, i.e. anything that has been plus one-d will be shown higher in the search results.
The main issue with Plus One is that it can completely change the order of the search results. So if a page has been optimised for a certain keyword, it will always be beaten to the top rankings by websites that have a higher plus one count. However this only happens if people are logged in to a Google account, and have friends that have plus one-d a website relevant to the search term used.
Of course, not everyone searching on Google has a Google account, so this will not effect absolutely everyone. Whilst more and more people will be signing in to Google for their new social network, Google+, not all searchers will be using this.
A less obvious feature of Plus One is that even if a site has been blocked by a robots.txt file, the site is made visible and searchable by Google’s robots if someone Plus Ones it. Whilst it is unlikely that a hidden page may be Plus One-d, it is still a concern for site owner’s who want to keep certain pages hidden. Again, the page would only be shown as a recommendation to a friend, and not in the regular search results.
The main benefit of Plus One is that if your website gets a good amount of plus ones, it will be regarded as highly relevant and highly creditable. It’s one of the best forms of word of mouth on the Internet, but at the moment it’s limited to those with a Google account. Whilst it’s still in its early stages, many reputable companies have taken it on board which has had a profound effect on it’s influence across the Internet. However, unless more people sign into Google and utilise their customised search results, Plus One will struggle to grow. Only time will tell if Plus One is here to stay.