The BBC concluded that the "Likes" you buy via Facebook advertising is mostly junk traffic by people who don't buy things 

Reshared post from +Mike Elgan

Facebook's Summer of Fail

Remember when Facebook was the company that could do no wrong? When all the attention and traffic and users were headed in droves to it? When founder and CEO Mark Zuckerberg was anointed as the new Steve Jobs?

Neither do I.

Facebook's Summer of Fail has shortened memories about the good times for Facebook, and focused attention on an uncertain future.

https://www.computerworld.com/s/article/9229964/Elgan_Facebook_s_Summer_of_Fail