creative effort might be also collaborative. The creative effort requirement is considered debatable. On the one hand the criterion of creative effort is not considered selective and has been shown only exemplarily so far. Therefore, the minimum amount of creative effort needed to qualify for UGC remains indistinct. On the other hand, defined UGC platforms do not always include UGC content only. For instance, the video sharing site YouTube displays also sponsored professional material (e.g. movie previews, TV series cuts). Overall, the creative effort requirement can be described by the content attributes flexibility as regards content, flexibility as regards technique and interactivity.