Search engines continually evolve and it is never so apparent when you search for something online and then receive a blanket of ads for something you were trying to get rid of; not something you were interested in purchasing.
For example, I recently was investigating the worth of a cash drawer that a customer wanted to unload. Several week later I still receive ads for websites that sell cash drawers. They follow me from search engines, to game sites, to Facebook.
Then there are the times when the ads are truly helpful---searching for a hard to find item and you are suddenly helped by one of those Facebook side items---directed to a website that has exactly what you are looking for at a great price.
And this is an example of why you should make sure that your Facebook page, Twitter, Pin It, and any other social media leads your customer to your website. If I find you on Facebook and your website is lost in your timeline, I leave without paying you a visit. The best use of Facebook has the company website right there at the top. And be sure to make it easy for people to share what you offer online and pass the word on about just how great you are.