It's sort of bizarre that he picks out Wikia as a negative example. The communities on Wikia can and do take their content somewhere else, including the entire edit history, attributions, and all. Original contributors retain copyright, and everything is clearly licensed under free licenses that permit the community to take it elsewhere (and commercially exploit it if they want; this is not a right that is reserved to Wikia). You can download the regularly-made content dumps easily; you don't need a special scraping tool. And finally, the software is open-source, so you can put a downloaded dump into a MediaWiki install in an afternoon.

How much of that can be said of your Stack Overflow contributions?