[binarytox1n]

Uh... if you sold it, did you retain the rights to the content in the sale? If not, I'd say your users are going to have to suck it up.

[Blackthorn]

I didn't sell the content, I sold the site.

The content was all licensed to the wiki under CC-BY-SA. So even if I could have legally sold the content, which I couldn't have because I didn't own it, I and my users could fork it however we want.

[Macha]

Nearly all wikis have content licensed under some form of creative commons. e.g. Gamepedia used CC BY-SA for older wikis and CC BY-NC-SA for new ones.