some digital media platforms can use criteria to choose stories which are different than traditional news value. for example, while the google news portal essentially chooses stories based on news value (though indirectly, through the choices of large numbers of independent outlets), users can set google alerts on specific terms which define personal subjective interests. search engines, news aggregators, and social network feeds sometimes change the presentation of content depending on the consumer's expressed or inferred preferences or leanings. this has both been cheered as bypassing traditional "gatekeepers" and whatever biases they may have in favor of audience-centric selection criteria, but criticized as creating a dangerous filter bubble which intentionally or unintentionally hides dissenting opinions and other content which might be important for the audience to see in order to avoid exposure bias and groupthink.