Google introduced a "+1" button for its users to recommend search engine results to friends from the Gmail contacts. It is similar to Facebook´s "Like" button.
The button works for search results and advertisements. Users can see how many recommendations there are for e. g. localities or recipes before trying them. With the button, Google adds human evaluation to the algorithmic results.
Google referred to its "+1" button as a "digital shorthand for ´this is pretty cool.´"