Social Marketing vs. PPC/SEO

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I've had some success with Facebook and Twitter in promoting some of my music and I think they're great platforms for that. I'd like to try my hand at marketing some other products/services with Facebook in particular, but I've heard some people claim that people on Facebook aren't really looking to buy. What do you think? Seems to me that someone looking for "Blue Widgets" is much more likely to type "cheap blue widgets" into Google than to wind up making a purchase as the result of a Facebook ad or recommendation. What do you think?