Users have been able to embed tweets onto websites for ages, but unlike replies and mentions, the writer of a tweet would never get notified whether or not their tweet was embedded onto a website, as well as which websites the tweet was embedded on. However, it seems Twitter is secretly testing this feature, and some users noticed it over the weekend.
First discovered by security expert Mikko Hypponen at F-Secure, Twitter seems to be field testing a feature called "Embedded on these websites," which offers a list of websites below a tweet to which the tweet is embedded on. Not only will this help Twitter users know what websites their tweets are on, but it also gives information seekers more info on a tweet by clicking through to one of the websites listed.
The feature appeared for a short while over the weekend (a time when Twitter traffic apparently isn't booming, thus being the perfect time test out secret features), but was eventually taken down and out of sight, but that didn't stop a few users from taking screenshots to record the evidence.
From what we're seeing, below tweets will be a list of websites that the tweet is embedded on, and it will include the website's name in bold and the article title next to that. From there, you'll be able to click on any of the articles to read more about a tweet, just in case you wanted to know more information than a 140-character tweet would allow.
However, it isn't clear as to whether or not we'll see this feature on all tweets, or just a select number of tweets, such as those only from verified Twitter accounts. As with past new features from Twitter, we're guessing the service will slowly roll it out to just a handful of popular Twitter accounts and then eventually open it up for all tweets at some point.