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Facebook has joined the hashtag revolution, introducing a tool on Wednesday that allows users to add the # symbol before a word to signify its topic. The topic would then be easily searchable by other users of the social network.

Of course, anyone who has used the microblogging service Twitter is familiar with hashtags, which have long been used there to organize public conversations. Right now, for example, #manofsteel is a popular hashtag on Twitter because of the coming Superman movie. Search for that hashtag on Twitter and you can see the global conversation about the topic.

Tumblr, Pinterest and other social networks also use hashtags, and Google announced last month that it was adding hashtags to its Google Plus service.

In a blog post, Facebook said it, too, wanted to make it easier for its users to participate in a common conversation.

“Every day, hundreds of millions of people use Facebook to share their thoughts on big moments happening all around them. Whether it’s talking about a favorite television show, cheering on a hometown sports team or engaging with friends during a breaking news event — people on Facebook connect with their friends about what’s taking place all over the world,” Greg Lindley, a Facebook product manager, wrote in the blog post. “To bring these conversations more to the forefront, we will be rolling out a series of features that surface some of the interesting discussions people are having about public events, people and topics.”

Starting Wednesday, users can click on a hashtag in Facebook and see a feed of what other people and organizational users are saying about that event or topic.

Facebook said users would also be able to click on hashtags that originated on other services, like Instagram, a photo-sharing service owned by Facebook that already uses the tool. Searching a hashtag will bring up posts with that tag made by friends and other users who have chosen to make their posts public.

The new hashtag service is immediately available to about 20 percent of Facebook users, with the rest getting it gradually over the coming weeks.

The company said it would roll out additional features, including trending hashtags, in the near future.