Google is rolling out its +1 recommend button across third-party web sites, as well as to Google properties, a day after Twitter introduced a "Follow" button for third-party sites.
The +1 recommend button was first introduced in March for Google search results and advertisements.
"Today, we're releasing +1 buttons to the whole web," Google said on its blog on Wednesday. The company said it had already partnered with a few sites where the +1 buttons will figure in the near future. Google is also introducing the buttons on its own sites such as Android Market, Blogger, YouTube, and Product Search.
"With a single click you can recommend that raincoat, news article or favorite sci-fi movie to friends, contacts and the rest of the world," Google said on its blog. "The next time your connections search, they could see your +1's directly in their search results, helping them find your recommendations when they're most useful."
Google also introduced on Wednesday tools that web masters can use to include the +1 recommend button on their web sites.
The company said it was continuing to roll out the +1 button for English-language searches on Google.com. Users who want to recommend search results and search ads using +1 earlier can opt in through Google's experimental search site. To see recommendations from friends and contacts in Google search, users have to be signed into their Google Account.
Twitter introduced this week new "Follow" buttons on third-party web sites, that allow users to discover and follow Twitter accounts directly from the web sites they visit. It also added a tool that enables web sites to add the Follow button.
A large number of web sites already provide links that invite visitors to follow them on Twitter. These links however take the user to the Twitter site, where they can then decide to follow the Twitter account.
More than 50 sites added the new Follow button on Tuesday, including a large number of news sites and some web sites of celebrities.
On the lines of the "Like" introduced by Facebook on third-party sites, the new Twitter and Google buttons will help these companies keep track of the sites that users visit, and their preferences, analysts said.