I, as a coinmarketcap user, was very disappointed with this because I had proven that the site only provided fake data and insiders (staff / employees) from Coinmarketcap used this site to benefit from trading. CMC staff / employees know which coins to pump and buy as many coins as possible.
They didn't really provide fake data, only relayed it.
Some exchanges were gaming their volume, and Coinmarketcap didn't up their game to filter those out. They're going to address it in the future, apparently:
“For instance, if an exchange with low traffic has $300M volume and just 5 BTC in its wallet, users will be able to draw their own conclusions without the need for us to make arbitrary judgment calls on what is ’good’ or ’bad,’” she explained.
So fake volume would still be reflected in the site, and it will be up to the user to judge their authenticity. This is better than arbitrary whitelists/blacklists in my opinion.
I don't know how Coinmarketcap works, but if all the listings and numbers are gathered automatically through the exchanges' APIs, then I wouldn't blame them. Otherwise, well, they're paid shills who shouldn't be trusted.