In my opinion, they are bound by the license that they set for earlier contributions -- they would be require to attribute those. This would only apply to contributions dated today or later.
However, there are a couple of wrinkles here: It's not on any page that users are required to see, so many users may not know that they are transferring ownership by editing. It's hard to argue that you agreed to a contract that you never actually saw.
The second issue is that TVT argues that this rule has always applied -- that the transfer of ownership was an assumption that you made when you clicked save page. I tend to agree with a stance more similar to that of the EFF -- that in the absence of a license, you only transfer a bare right to distribute, and to make incidental copies in the process of distribution. Since the license is on every page, the assumed license most likely shifts that which appears on the wiki page -- CC-BY-NC-SA (previously CC-BY-SA). Again -- not a lawyer here, just an experienced policy analyst.
In any case, I'm going to err on the side of caution with this one. There's no need to antagonize TV Tropes any more than we have to by our mere existance. After all, they seem to be perfectly capable of antagonizing their own user base.
-- ∇×V
However, there are a couple of wrinkles here: It's not on any page that users are required to see, so many users may not know that they are transferring ownership by editing. It's hard to argue that you agreed to a contract that you never actually saw.
The second issue is that TVT argues that this rule has always applied -- that the transfer of ownership was an assumption that you made when you clicked save page. I tend to agree with a stance more similar to that of the EFF -- that in the absence of a license, you only transfer a bare right to distribute, and to make incidental copies in the process of distribution. Since the license is on every page, the assumed license most likely shifts that which appears on the wiki page -- CC-BY-NC-SA (previously CC-BY-SA). Again -- not a lawyer here, just an experienced policy analyst.
In any case, I'm going to err on the side of caution with this one. There's no need to antagonize TV Tropes any more than we have to by our mere existance. After all, they seem to be perfectly capable of antagonizing their own user base.
-- ∇×V