One of the reasons for its popularity is that the user's own video and the alternative variations from popular artists' videos may reach an audience of millions, says a new study from Finland's Aalto University.

Music is the most popular YouTube content by several measures, including video views and search activity.

People re-use original music by popular artists to create their own alternative video variations, which may reach an audience of millions and can be found alongside any popular music title.

"These variations, that we call user-appropriated videos, are readily available and well promoted on YouTube. This is what makes YouTube an interesting music service," said lead researcher Lassi A. Liikkanen.

Lyrics and still videos, which only include music, rank highly in YouTube search results. A popular video, say a new Beyonce song, may share its audience collaterally with similar user-generated videos because they appear next to one another in the search results and suggested content, the study said.

The researchers named this the halo effect. In this study, the researchers created a typology of YouTube music videos."Our analysis found three primary music video types: traditional, user-appropriated, and derivative music videos," said co-researcher Antti Salovaara.

Through a series of qualitative and quantitative studies of YouTube content, researchers studied both the popularity of music videos and the attention they get from the audience.

The study showed that users are willing to listen to music from Youtube even without video content. They are also happy with music with rolling lyrics over a still photo, cover versions, and even parodies of the authentic music content.