Twitter is quietly testing a new metric to measure the popularity of posts. The latest addition is a bookmark counter, which shows the number of times a tweet has been added to a user’s bookmarks. The counter appears alongside other public metrics like retweets, quote retweets, and likes.

At present, the feature is only available to iOS users who visit the tweet details page. However, Twitter has confirmed that it has plans to expand the feature to other platforms soon.

It’s worth noting that unlike other metrics, the bookmarks counter is not clickable. This is because bookmarks are private, and Twitter has no intention of displaying which accounts have added a tweet to their bookmarks.

While this new feature may not be particularly useful to most Twitter users, it is likely to be of interest to the platform’s CEO, Elon Musk. Musk has tweeted about bookmarking on several occasions, calling it a “de facto silent like.” He has also praised the ability to bookmark a tweet from its details page as a “major Twitter improvement.”

However, some Twitter users may view this new metric as yet another thing cluttering up the interface. This sentiment is similar to the view counter, which some users find unnecessary.