If anyone’s having trouble figuring out why MySpace would want to buy social music site iLike, here’s the reasoning:

Until now, MySpace has addressed the music community with “MySpace Music,” dedicated pages for bands and recording artists.

With iLike’s acquisition, MySpace doubly-reinforces its place as the go-to place for musicians. It also puts the company in a dominant position within rival Facebook’s own site.

In effect, MySpace is doubling-down on music as its hook for attracting and keeping users. It’s already mapped out this strategy with the idea of “social DJs” as social media musical vanguard; iLike would seem to be an essential tool in moving that concept forward.

This is a return to its roots, actually: Remember that a key driver in MySpace’s rise as the first widespread social network website (well before the dedicated “MySpace Music” initiative) was its cultivation of musicians, especially obscure indie bands and their fans. Now that it’s lost buzz and user numbers to Facebook, it’s a good bet for MySpace to reinforce itself as a niche socnet. Music is one of the more reliably sticky content formats for keeping eyeballs glued to the screen, and adding iLike’s 50 million users affirms that strategy. It’s a dirt-cheap one, too: At the rumored $20-million pricetag, iLike is selling for many multiples less than the $280 million that it cost CBS Corp. to buy Last.fm.