This is complicated and the risks real.
My company helps companies grow (ie we market their brand / company) in many different ways, including building a Facebook fan base, so it looks totally organic or by establishing personal branding.
Can I endorse a company or product when they pay me to help them market their company with social media? Apparently it is illegal. Even if my endorsement mirrors my real beliefs in a product or company.
Kinda like me endorsing a laxative product – like I really use it and love it, even if I don’t. If I am paid for my marketing services, Facebook building or other social marketing and seem to endorse it (ie “Like” it), the FTC finds it illegal.