Twitter has accused Google of making information harder to find by fusing Google+ with its search results.
In a statement following the announcement on Tuesday of the deep integration of Google+ and Google Search, Twitter said the change sidelines tweets by only giving extra prominence to Google+ content. Google responded by saying Twitter had sidelined itself by letting a key data-crawling agreement expire.
"Twitter has emerged as a vital source of… real-time information, with more than 100 million users sending 250 million tweets every day on virtually every topic. As we've seen time and time again, news breaks first on Twitter; as a result, Twitter accounts and tweets are often the most relevant results," Twitter said in a statement sent to ZDNet UK sister publication CNET News.com.
"We're concerned that as a result of Google's changes, finding this information will be much harder for everyone. We think that's bad for people, publishers, news organisations and Twitter users."
Prior to that official statement, Twitter general counsel Alex Macgillivray, who used to be a lawyer at Google, tweeted: "Bad day for the Internet. Having been there, I can imagine the dissension @Google to search being warped this way."
Google said it was taken aback at Twitter's characterisation of the situation, as an agreement between the two companies to give real-time search prominence to tweets had expired halfway through last year.
"We are a bit surprised by Twitter's comments about Search plus Your World, because they chose not to renew their agreement with us last summer, and since then we have observed their rel=nofollow instructions," Google said in a Google+ post.
Google also told News.com that it hoped Twitter and Facebook would at some point also feature in the social results that it has just made more prominent.
"Google does not have access to fully crawl the content on some sites (i.e., Twitter and Facebook), so it's not possible for us to surface all that information," the company said. "Ushering in the new era of social and private data search will take close cooperation, and we hope other sites participate so we can provide the best possible experience for our users."