Source: Facebook.

There's a lot of copying that goes back and forth between Facebook (NASDAQ:FB) and Twitter (NYSE:TWTR). More recently, though, it seems Facebook is copying more features from Twitter than vice versa. Facebook's latest exploit is a copy of Twitter's content curation tools for journalists. Facebook's tool set is called Signal.

Signal will let journalists track what's trending on the social network and search for more pictures, videos, and posts around a specific story. It will also let them find information about public figures on Facebook, and package it up and embed it on their own websites. This is remarkably similar to Twitter's own Curator tool, and it represents yet another attack by Facebook to supplant Twitter as a source for news.

Facebook befriends journalists
This is only the most recent step by Facebook to attract more attention from journalists. Journalists have traditionally used Twitter to discover and break news, but Facebook wants to change that.

News is a growing piece of Facebook's core experience. A recent Pew research poll found that 63% of Facebook users get their news from Facebook. Interestingly, the same percentage of Twitter users said the same about Twitter. However, Twitter still maintains a healthy lead when it comes to users following breaking news stories.

The new Signal tool offers the opportunity for journalists to use Facebook content to help readers follow a breaking news story. Additionally, Business Insider reports that Facebook is working on an app that allows publishers to push notifications to readers with breaking news alerts. On top of that, Facebook just updated its Mentions app for verified accounts to allow journalists to live stream content to their followers. Those videos will remain on Facebook permanently unless the author deletes them.

All of these updates are designed to make Facebook a bigger source of news than it already is. And that's bad news for Twitter.

Twitter's biggest strength is under attack
Twitter's biggest strength, by far, is its ability to attract breaking news from journalists and average users alike. And with the default setting that every tweet is publicly available, there's a lot it can do with its content. That could propel a journalist or even an average user into the limelight as they end up covering breaking events on Twitter, and people quickly retweet or embed that content into their own websites.

Now Facebook is making the exact same functionality possible through Facebook. And with a significantly larger audience -- 1,490 million versus 304 million -- Facebook is much more attractive to journalists looking to reach the widest audience. Likewise, journalists are capable of tapping into a much larger user base with Signal.

The potential for journalists to more easily discover and syndicate posts from Facebook is a significant threat to Twitter. Twitter has talked about the opportunity it has with syndicated content, noting that its tweets see 185 billion impressions on other publishers' websites and apps every month. If Facebook's Signal improves the amount of Facebook content in syndication, it could nullify whatever impact that has on advertisers' decisions.

Twitter's plan to defend its strength seems to be centered around Project Lightning -- an upcoming feature that will offer a new user experience of curated content. Twitter's management says Project Lightning may feature breaking news stories, making it easier for users to see how a story unfolded on Twitter and in real time. Project Lightning will also feature curated feeds of big events like awards shows and sports games.

During the company's most recent earnings call, interim-CEO Jack Dorsey and CFO Anthony Noto both talked up the potential they see in Project Lightning. Twitter will run its first major ad campaign featuring the new product feature and hopes it can attract a wider audience. The expectations are set high for Project Lightning, and in the meantime, Facebook continues to chip away at Twitter's strength. If Project Lightning doesn't deliver, it could be a tough time for Twitter shareholders.