Search is Google’s core business and it’s very cautious with every new feature it has plans of rolling out. These are tested amongst a few users until they are given a green signal for the full roll out.
Google is out testing a new feature for its search that enables users to decide what amount (length) of summary they require to appear for their search results. The available options include Small (has no summary displayed at all), Medium (Summary equal to the current length) and Long )one that extends up to four times the present).