Billboard Hot 100 lists to count on-demand streaming

Billboard's been tracking the popularity of music for decades, first looking at sales, and then for some of their charts (like the Hot 100) adding in radio plays.  Now, in recognition of the growth of on-demand music streaming, its going to factor those choices into the mix.
  Specifically, Billboard is going to include information from the Nielsen BDS monitoring of streaming activity for its On-Demand Songs chart, and also factor those into its premium Hot 100 chart. With the rise of a number of subscription on-demand streaming services (like Spotify), and Cloud-based streaming from personal music collections, Billboard argues that this is a growing and significant component of the music market that can't be ignored if you're truly seeking to measure the popularity of songs and artists.
  Some numbers from the Nielsen BDS give an indication of how big music streaming is - in the first 70 days of 2012, more than 4.5 billion audio streams were tracked, growing to a record 625 million ilast week.  Compare that to the average 2.5-5 million online song purchases per week during 2011.
"The methodology behind all of the Billboard charts is ever-evolving to incorporate new technologies and the emerging ways consumers listen to and buy music" said Silvio Pietroluongo, Billboard's director of charts. "Accounting for an interactive medium such as streaming, both in the Hot 100 chart and the On-Demand Songs chart, provides an even more accurate gauge of the songs that are truly the most popular in the country."
  Of course, not everyone is happy with the move - mostly feeling that on-demand metrics might dilute current radio plays and sales numbers with older favorites.  On the other hand, I'm old enough to remember that Pink Floyd's Dark Side of the Moon remained on Billboard's weekly Top LP chart for 15 years, without much complaint from music companies or the radio industry.  Besides, Billboard's got lots of charts, and most don't include on-demand streaming... yet.
  Still, Billboard's creation of new focused charts and inclusion of on-demand streaming in its Hot 100 chart can be seen as a recognition of the growth and impact of this newer distribution system for music..

Source -  Hot 100 Impacted by New On-Demand Songs ChartBillboard