Google said on Wednesday that it would end its Google Answers service, marking a rare decision by the search company to trim its rapidly-expanding portfolio of services as it shifts its product development focus to improving those considered to have the greatest potential.

The admission of defeat also points to an area where Yahoo, though widely seen as still lagging Google in search, has outstripped its arch-rival.

Google Answers, launched four years ago, provides online answers to users’ questions by drawing on contributions by real people, rather than the algorithmic search results for which Google is better known.

According to ComScore, in June the service attracted just under 1m users in the US, compared to the 12.3m for the similar Yahoo Answers. Yahoo itself on Wednesday claimed 60m users worldwide for the service.

Google’s retreat appeared to offer some vindication for Yahoo’s decision to concentrate more of its development on so-called “social media” services, which rely on direct input from its large network of some 500m users to help shape the product.

Adding a human element to either supply content directly or “filter” information garnered from the Web can yield more useful results than machines alone, it argues.

The Answers service has been singled out by Google executives in the past as one that has failed to achieve critical mass. However, the timing of the decision to end the service underlined the recent signs that Google is nearing the end of a phase of rapid new-product launches.

Google said it had only closed two services before this: Google Viewer, which organised search results in a single scrolling slideshow, and Google Voice Search, a voice-activated service.

In an interview with the FT recently, Sergey Brin, Google’s co-founder, said the group planned to concentrate more on adding new features to existing products, rather than creating more new ones.

In a post on its company blog, Google said that more than 800 people had supplied material to the Answers service in its four years.