Record labels big and small are working toward the goal of turning every social network profile, blog and fan site into a digital music storefront.

Their ultimate objective is an environment where music fans could stream their favorite music from their personal Web pages and post a "buy" button next to each track. If every site's visitor could, with the click of a button, place that same buy button on his or her own site as well, every fan could become a point of purchase and a channel for promotion.

By sidling up to the social networking scene, labels hope to goose a digital download market that is not yet making up for falling CD sales. However, despite their popularity, it's hard to say whether social networks can translate their promotional prowess into sales.

At first blush, it seems like a slam-dunk. Social networks are enormously popular, with MySpace counting 70 million active monthly users alone. Adding to their sheer size is their ability to instantly connect like-minded users based on shared interests, location or real-life associations. These "friends" can virally pass along content from one to another quickly and easily by simply sharing a small bit of code-called a widget—between individual profiles.

For instance, artists on MySpace often allow fans to post a stream of their latest single to their individual profiles. More than 9 million fans have posted Fall Out Boy's "A Little Less 'Sixteen Candles,' a Little More 'Touch Me' " to their respective sites.

Click here to read more on which companies are leading the charge, the challenges of this model, digital rights management and what role social networking will play in the future of music.