I would give good money to see the algorithm Billboard uses now to choose the most popular song in the country. As the sudden success of Baauer's "Harlem Shuffle" proves a viral video can turn the charts on its heads and really, it is hard to decide if the Top 200 has any real meaning any more. It seems wrong to include Youtube streams in sales (really most popular). If you are paying really really nothing for the music, how can it end up on a sales chart?
I don't have the slightest what the answer is. Once you include streaming, the floodgates opened up and once you move away from the self-evident: sales and only sales, what exactly are you being informed of?
The flip side of that is now anybody can have a hit and there is nothing the labels or the musicians themselves can do about it. Some musician should make a video of a cat falling off a tree and stick their song on it, next thing they know they will be a best selling rock band and more power o em, everything will be a con job. As Joe Steinhardt noted, there will be no mystery left. There is n mystery left. The charts have become a weird game of hide and seek.
On the THIRD HAND, suddenly pop success truly becomes like a lottery ticket. Nothing matters that much, not quality, no ability, just does it catch on?
But where does that leave those of us (wrongly, perhaps) who see music as an XTreme sport with winners and losers, or, to put it another way, how do we know what people are actually spending money on?