While there is information online suggesting that bookmarking on subscription streaming services and social media platforms leads to increased engagement, there is no evidence that bookmarking leads to increased watch time. Only the percentage of titles on a Watchlist that is typically watched to completion is available, and available information indicates that only a small percentage of titles on a Watchlist are watched in their entirety. Despite this low completion rate, there are figures suggesting that the bookmarking feature is widely used across subscription streaming services and social media platforms. The act of bookmarking itself is a form of engagement. Below, we explain how we arrived at these findings, and we provide further details as well.
   

We conducted a press search and looked for articles or reports covering watch lists, favorites, and bookmarks on streaming services and social media platforms. This initial step turned up only one helpful result, however, and this one source is Diggs' article "Why We Never Watch Things On Our Watchlists." There was no proof in this article of whether bookmarking leads to increased engagement and watch time, but we learned from this article that only a small percentage of titles on a watchlist are watched to completion. We learned as well why, despite this fact, watchlists are still necessary.

Proceeded with a search for surveys of users of subscription streaming services and social media platforms, as we figured that these surveys may contain insights as to the impact of bookmarking on engagement and watch the time. Unfortunately, we were unable to find such surveys.

As a workaround, we searched for the bookmarking features of some streaming services and social media platforms provided and looked for articles and press releases covering these features. This strategy proved effective as we were able to learn why Netflix, Facebook, Instagram, Twitter, and Hulu have launched or enhanced their bookmarking features. We were able to gather a number of insights into the number or percentage of users utilizing the bookmarking feature and the demand for a bookmarking feature among users of streaming services and social media platforms. These insights informed our analysis of whether bookmarking increases engagement.
           
Please note that we typically use sources published in the past 24 months, but given that we were trying to understand why subscription streaming services and social media platforms have launched bookmarking features and how this relates to engagement, we looked beyond the past 24 months for sources. Some bookmarking features were launched more than two years ago. Nevertheless, most of our sources below were recently published.

DOES BOOKMARKING INCREASE ENGAGEMENT?
Information suggests bookmarking does increase engagement. Subscription streaming services and social media platforms have been launching or enhancing bookmarking features in the past few years - proof there is indeed a demand among users for a feature that will allow them to save videos to watch at a later time.

Netflix, for instance, launched in 2013 its My List feature, which serves as a repository for television episodes or movies members wish to watch at a later time. From customer feedback, Netflix learned that members wish they have the option to set aside shows and movies they find interesting while browsing so when they do have time to watch, they can easily go back to these titles. In a press release, Michael Spiegelman, product innovation director at Netflix, wrote "our members frequently tell us that they would love to be able to set aside some of the movies and shows they discover when browsing Netflix, so they can have an easy place to access them when they’re looking for TV shows and movies to watch." The My List feature comes with automated sorting where Netflix's algorithm arranges the titles in the order it believes the member will most likely watch them. While this automated sorting is optional and can be disabled, tests had shown the majority of members appreciated the automatic sorting.

Facebook first introduced a "save for later" feature in 2014 and then expanded on this feature in 2016 with a Save to Facebook feature for the web. The launch of the Save to Facebook extension was Facebook's strategy for increasing the number of people using the save feature. At the time the Save to Facebook was rolled out, Facebook already had around 250 million people utilizing the save feature each month. Now, it appears that number has increased to 300 million.
    
Instagram launched its bookmarking feature in 2016 then enhanced the feature further in 2017. Since 2016, a user has the option to save an Instagram photo or video to his/her Saved section by tapping the bookmark icon at the bottom right of said photo or video. And since 2017, a user has the option to "organize saved posts into individual collections" similar to what users do on Pinterest. The only difference from Pinterest is that the collections cannot be made public (yet). At the time the Pinterest-like feature was launched, Instagram already had 46% of its users utilizing the save feature, and 29% of saved posts came from businesses. The Saved Posts feature is a part of the "Instagram engagement family."

Twitter began testing bookmarking in late 2017 and launched its Bookmarks feature in 2018. The Bookmarks feature is an improvement over the Favorites feature as it allows users to privately save posts they do not necessarily like or love. The Bookmarks feature was "something people have asked for because of how much news circulates across Twitter, often including links to longer articles you don’t have time to read at the moment, and an increased desire for privacy around their saves."

Hulu has introduced its user-controlled My Stuff watchlist feature in 2017 in response to users' clamor for a watchlist they can control.

We believe that Netflix, Facebook, Instagram, Twitter, and Hulu would neither launch a bookmarking feature nor enhance an existing bookmark feature if it sees that bookmarking does not translate to increased engagement. They have direct access to user data and can readily tell if a feature increases user engagement.

DOES BOOKMARKING INCREASE WATCH TIME?
There is no evidence online that bookmarking on subscription streaming services and social media platforms increases watch time. Streaming services and social media platforms may have already studied this and decided not to disclose the results. We could not find any information in the public domain that indicates or suggests the watch time increased in comparison to when the bookmarking feature was not yet available. What we found was information on click rate and completion rate (the percentage of saved videos that users actually watched to completion). Please note, however, that the rates we were able to find were specific to services that are not part of the list of companies provided in the details of this request.

On streaming service JustWatch, 5% to 10% of  the titles on a Watchlist are clicked by users, while on streaming service ReelGood, "75% of the titles on active users' watchlists receive no user engagement." Lastly, on Letterboxd, a social network for film enthusiasts, 16.8% of the titles on a watchlist are watched to completion on average. Completion rates vary between people who use the watchlist to store titles they intend to watch and people who use the watchlist to store favorites (titles they love and intend to rewatch).
       
Despite the low completion rates, watchlists are not necessarily useless. On Netflix, for example, watchlists help shape recommendations, and recommendations, in turn, help users discover content they otherwise would not discover on their own. Bookmarking is also a great way for users to engage with the platform, curate content, and make the digital space their own. On Netflix, adding titles to My List is something a new user would do to personalize his or her account and establish his or her identity and aspirations.