The online video streaming giant said Monday in an email to Fortune that the ads aren’t paid commercials and are among the “hundreds of tests every year so we can better understand what helps members more easily find something great to watch.”

News of Netflix’s testing of in-house ads was first reported on last week by the trade publication Cord Cutters News, which noticed that several United Kingdom Netflix subscribers were commenting on Reddit about seeing ads for shows like Better Call Saul.

Netflix (NFLX) said that the ads are extensions of a preview feature it debuted in 2016. At the time, the company said that they were not “teasers or traditional trailers” and instead were a collage of clips from a particular show that highlight “the story, characters and tone of a title.”

The latest tests show that Netflix is trying to learn whether its previews are compelling enough to entice subscribers to watch other Netflix shows or movies.

“In this particular case, we are testing whether surfacing recommendations between episodes helps members discover stories they will enjoy faster,” a Netflix spokesperson told Fortune. “It is important to note that a member is able to skip a video preview at anytime if they are not interested.”

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Additionally, Netflix said on Monday that it has removed the ability for people to post their own reviews of shows and movies on Netflix because of declining use.