How do you find facebook as a marketing channel?

There are various ways to market your product online and social marketing is just one of those. In comparison with other strategies such as article marketing how heavy do you use facebook as one of your strategies to market a product?
Facebook Marketing

Does anybody know anything about Facebook marketing?

I signed up for Facebook about 4 months ago as I have read that Facebook marketing is a great way to make money from your websites, but I don't see how it works. How do I market on Facebook without spamming my so-called friends?

If a retail store wants to expand into ecommerce, what are tax advantantages of facebook marketing?

How would marketing the new company through Facebook vs. other more traditional marketing strategies benefit the company tax-wise. I am particularly concerned with avoiding nexus and sales and use tax. Does anyone know the teax implications of facebook advertising, etc.? Thank you in advance!