"Search plus your world" was billed as a major change to the leading Internet search engine.
"There is a huge amount of content on the Web today but, at a certain point this content is nameless and faceless," Google's Ben Gomes told AFP.
"The most relevant content is from people you know, so we are introducing your personal world to search."
People signed into Google accounts will be able to have the search engine include in results content approved for sharing by them or friends at Google+ or Picasa.
"I've been trying it out and it really changes the nature of search for me," Gomes said. "Now when I search for Bangalore I not only see information about the city but I see pictures of the house where I grew up."
A cursor hovering over an image will reveal where the picture was shared online and by whom, according to Gomes.
"We want to show you your personal data and data from friends," Gomes said. "We want to use Google+ and circles as the underlying infrastructure."
Google's social network lets users share comments, pictures, videos or other online content based on which "circles" friends, family, co-workers or acquaintances fall into.
Google is also enhancing searches for information about people by factoring in Google+ posts.
And Google will show which celebrities or other prominent people are commenting at the social network about topics of searches.
Personal data woven into results is protected with encryption and other security on par with that used to safeguard Google's email service, according to Gomes.
"We've gone above and beyond on control because we know people are sensitive with personal data," he said.
Google plans to weave its social network into an array of its properties and services as it builds an online community in a market dominated by Facebook.
Globally popular microblogging service Twitter was quick to blast the changes to Google's search engine, arguing that real-time "tweets" with dramatic ramifications will sink deeper on results pages.
"As we've seen time and again, news breaks first on Twitter; as a result Twitter accounts and Tweets are often the most relevant results," the San Francisco-based startup said.
"We're concerned that as a result of Google's changes, finding this information will be much harder for everyone," Twitter continued in a statement emailed to AFP.
"We think that's bad for people, publishers, news organizations and Twitter users."
Twitter messages are public and are blended into online search results. Posting Google+ pictures and posts high on results pages could relegate tweets to lower positions that are less likely to be noticed.
Twitter's lament surprised Google, since the one-to-many text messaging service has restricted the search engine from ranking most tweets for since it opted not to renew an agreement with the Internet titan last year.
"We are a bit surprised by Twitter's comments," Google said in a message at its online social network.
"They chose not to renew their agreement with us last summer, and since then we have observed their rel=nofollow instruction."
"Rel=nofollow" is a computer code that instructs Google search ranking mechanisms to ignore tweets with Internet links to websites.
