The US equivalent of the singles chart, the Billboard Hot 100, is to get a 21st-century makeover with streams from the likes of Spotify being included for the first time.

Currently the Hot 100, the US music industry standard singles popularity chart, is based on radio play and sales; the tracking-week for sales begins on Monday and ends on Sunday, while the radio play tracking-week runs from Wednesday to Tuesday.

The weekly chart will now include data from streaming-music sites such as Spotify, Rhapsody, Slacker, Muve Music, Mog and Rdio to its calculations of a song's popularity.

The decision to add the streaming data comes as Billboard editorial director Bill Werde described the current generation of music-streaming services as having hit "a critical mass" among users.

During the week that ended March 4, there were 494 million songs streamed across the counted services, according to Nielsen, and just 27.1 million song sales.

However, the flip-side is that there are criticisms that services like Spotify aren't making enough money for the artists involved. Last year, STHoldings pulled its music from streaming music service, stating that the business model was hurting, not helping, the industry.

The indie label said at the time: "Despite these services offering promotion to many millions of music listeners we have concerns that these services cannibalise the revenues of more-traditional digital services."

The Wall Street Journal reports: "Download sales are much more lucrative for record labels than online streams, generating 70 cents or more in revenue per song sold, compared with less than a penny per stream from services that let users listen to an unlimited amount of music for a flat monthly fee."

Here in Blighty, the UK Singles Chart is compiled by The Official Charts Company on behalf of the British record industry and lists the weekly top-selling 200 songs based upon combined record sales and download numbers. Downloads were first included in 2005 - there are no plans as of yet to include streams.