I'll just say this.
The reason for constantly changing the algorithm is that they still cannot get it right. It is an admission that they, their programmers, designers, people in charge, are useless.
The constant release of updates and incoherent tweets from the humorless moron called Matt Cutts - who is regarded as a guru simply by the fact that he appears to wield power.. although not control - demonstrates how utterly rubbish this whole exercise has been.
It has taken this monopoly abusing, tax-evading, eavesdropping corporation over TWO YEARS of tweaking and fiddling around...
... and they still can't get it right!.
Anyone else would have been sacked long ago. It is pathetic.