Negative - You were scammed or you strongly believe that this person is a scammer.
While the website does give that description for the negative feedback it doesn't hold true in practice. Account buying is mostly used for scamming, therefor DT members give negatives on it.
A great example of the double standards on this forum the community is complaining about
This forum should be considered unmoderated. While some obviously illegal things do get deleted and taken care of to limit the liability of the website owner and admins, there is very little moderation going on in the marketplace. As such, DT1 and DT2 has stepped in to try and fill that void with some sort of moral standard. And since it is mostly an unorganized group of individuals there are conflicting moral agreements and things like that. Those people are literally all we have in terms of scams/reprehensible behavior.
You can say it's illegal, and maybe some things are, and certainly there is rampant scamming which is illegal, but Theymos will probably not respond to subpoenas given to him for user data even if you somehow found him and got a lawyer in his country to issue it.
So this forum is great for public discussions but very poor for marketplace activities or anything involving money, which I've come to understand from being a member in a heavily moderated forum that was made for marketplace transactions. That forum even goes as far as creating hashes of IP addresses and displaying them and all matching IP hashes publicly to see if the same user is coming back so they can prevent them from scamming. The moderators and admins actively view first posts to see if a non-home IP address is being used and if not issue a huge warning about that user. Maybe Bitcointalk just isn't the forum for you, and that's ok. It serves a good purpose and is flawed, but nobody should really be mad about that.