"YourSteamKey" lol Why would anyone use this?

Flogging is too good for them.

I mean, it's a service that collects data on your keys activation/distribution - You pay for the service if you want said service, or not, if you don't; it's entirely your choice. I don't see any harm to this other than I certainly would not trust them with my keys. Other than that, I've seen much worse.

Well from what i see this is "tool" for devs or other people that have to manage a lot of keys at once. Apparently thanks to this site you can check if keys were used or if people are playing game youre giving away (and thats bit creepy, why 3rd party site can track if i'm playing game or not? D:).
Anyway this way it makes bit more sense, but still i wouldn't pay 10$/month for this and for sure i woudn't trust them with my keys.

"Harmful web site blocked"

when you give them your Steam key, they give you a proprietary key that is 66% larger/longer than Steam keys.

To be fair, Steam keys aren't exactly bruteforce-resilient, so it's no surprise that they chose a longer format, which doesn't really matter since it's meant to be shared as a link.

Gotta be one of the most cringey and shady things to charge people $10/month to give away their keys.

Their "value", or at least what they sell, is the creepy stats as shown on their "features" page. I don't like this either, but I'm not sure this qualifies as shady, just yet another bloody tracking service...