Facebook does not drive direct sales, contrary to the hopes and ambitions of businesses everywhere. It is primarily a marketing tool, and the sooner your company realizes this, the sooner your strategy for engagement will put Facebook in its rightful place.
Facebook is useful for 3 things
1. Branding
Facebook is primarily a tool meant to keep relationships healthy and positive in a social world. Because so many use Facebook and, to some, Facebook IS the internet, just being available on Facebook is a simple step that makes sense.
As a branding tool, Facebook, like every other social media platform, allows you to influence your reputation by sharing content you would like to be associated with and by earning commentary and engagement that influences the sentiment around your brand. As the famous video asks, do you like what people are saying about your brand?
2. Marketing
If you're willing to pay for it, Facebook advertising can help you reach new potential community members (customers and clients, if the stars align). It's advertising and analytics platform is so robust and powerful that you can be very specific about who you want to reach with your posts.
And paying for it is the ONLY way to reach new people on Facebook anymore. It used to be that if you had 1000 people like your brand page, 1000 people would see what you post. Not anymore.
Facebook was not built for when things get noisy - with 1 billion+ people on Facebook, the average user would see over 1500 items in their news feed every hour if Facebook didn't filter it for you. So if you want people to see your stuff, you need to pay Facebook.
Of course, good marketing drives sales. Otherwise, why engage in it? Retail businesses, especially, report significant sales growth from effective Facebook use. But marketing is primarily about generating awareness and demand for what you sell, not selling it on the spot. Because people don't go to Facebook with buying in mind, calling on people to buy on Facebook isn't super effective.
3. Building relationships
As far away as most businesses are from understanding that building relationships with customers is THE great gift that social media has introduced to modern communications, it is. And Facebook is a great tool for liking people's stuff, commenting on it, and generally participating in the lives of others. If you're not doing this, you should ask yourself what is social about your media strategy.
Facebook is a relationship and reputation building tool, primarily for consumer-focused businesses. In most cases, Facebook isn't a lead generating platform (Pinterest and Linkedin are) and it is limited in how effective it is at helping new people discover you (Google+ and Twitter are).
Facebook is now the great social forum where businesses can get to know their communities and build a social reputation. Budgets and expectations should be built around this understanding.
How social is your business on Facebook?