Both Facebook and Twitter are part of the Ads Integrity Alliance and have policies in place to keep out sketchy advertisers, but that's clearly not keeping some from slipping through the cracks. Without much oversight from the social networks themselves, exercising common sense is key; if an ad sounds too good to be true, it probably is. In my case, for example, I know if I'm seeing an ad for a pair of Yeezys that cost less than their retail value, there's no way those shoes are the real deal. Not only that, but the name of the account advertising them -- something like "Adidas Yeezy 350 $119" -- is a telltale sign that the products are unauthorized.

An ad for fake Adidas Yeezys on Instagram.

According to a report by the Organization for Economic Co-operation and Development (OECD), the global trade of counterfeit and pirated goods amounts to nearly half a trillion dollars per year, and the industry is now trying to expand to Facebook, Instagram and Twitter, which are home to a combined hundreds of millions of users. In 2015, the US Department of Justice said it would crack down on counterfeits sold online. Outgoing Attorney General Loretta Lynch said back then that her plan was to work with tech companies such as eBay on providing them with "the right analytical tools" to fight intellectual-property violations on their sites.

Amazon has been grappling with this issue as well, especially as more brands find counterfeits of their products being sold there -- remember those Apple chargers? To alleviate this, Amazon recently started asking merchants for proof of legitimacy and a one-time $1,000-$1,500 listing fee before selling products from Adidas, Asics, Hasbro, Nike and Samsung. In theory, this should filter out the bad apples, but the initiative will eventually have to cover more brands (not just the major ones) if it wants to truly succeed. But until that happens, Amazon is going to keep getting sued by people who think the company is benefiting from sales of infringing products.