It's really easy, especially when you're first starting out, to get excited and register domain names and use registered trademarks from large companies in really illegal ways.
Bad Example: http://youtubesecrets.com/
The domain name itself violates Google's registered trademark by including 'youtube' in the domain in a way that is totally referring to their intellectual property. The website there has Clickbank's disclaimer on it but something tells me their compliance department never actually OKed this because it's a blatant violation of trademark. Also, it posts "As seen on" with a lot of other registered trademarks, which is also risky. While it DOES include decent trademark disclaimer language in the footer, the usage definitely has enough gray area that this website would get cease and desist notification and the hosting of the website could be contacted for a takedown. Since it's actually selling a product based on Google intellectual property, it could get worse.
As somebody that's actually been forced to remove registered trademarks from a website I created in the past, I can tell you that the lawyers will obligate the removal of unlicensed usage of registered trademarks if they ever got wind of this.
Is the owner going to get away with this? Probably, but it's dumb to do (unless you're knowingly black-hatting it, in which case you do it knowing the potential consequences, right?
Good Example: https://www.tubesift.com/
It's a product for YouTube as well, however the domain name, the logo, and usage of images is all appropriate. It also includes the necessary disclaimers in the footer as to the slight usage of trademarked terms. This is the legal way to do it.
You don't HAVE to break laws to kill it in this industry. Although I suppose you can get away with a lot of it if you want, I'm no whistle blower.