All information available on ModEnc is public domain. The moment you save your words here, you accept that they can be used by other users beyond your control, that your words may be edited, improved, deleted or otherwise altered without your consent. Or, as the note below the editing window puts it: If you don't want your writing to be edited mercilessly, then don't submit it here.
You do not own any content available on ModEnc. The only exception from this are your own, unaltered, marked tutorials. However, the moment they are altered, integrated, improved or anything, they cease to be your original, possessed creation, and as such you cannot claim ownership anymore. This is important for the next paragraph:
The information on ModEnc belongs to all of us. Ergo, you have not only the right to edit and add to it, but you also have the right to use it however you like1. In order to make sure, however, that credit is given where credit is due, you're required to make known the text is from ModEnc, wherever you use it. That way, people can look up newer versions, can correct errors and look up the authors. The only exception, again, are your own, unaltered, marked tutorials, as it'd be stupid to require you to mention ModEnc when you quote your own tutorial. However, the pattern stays the same: If your tutorial ceases to be your own, through modification or otherwise, you're quoting someone else's work just as you're quoting your own, so you are morally obliged to tell people it's from ModEnc.
1 In the past, we had a policy that prohibited the use of ModEnc's content to create another encyclopedia; since we cannot allow you to use it for everything, and then prohibit a use, that point is moot. However, the argumentation stays the same: Dividing the community by working on two seperate encyclopedias helps no one, especially not if they base on the same pages. Our chances for one grand encyclopedia are much higher if we all work together.
In addition, one must not forget that you'd be required to credit ModEnc on almost any page - which doesn't actually look good.
After all, we're very cooperative - if you talk sensible to us. If you have an idea for expansion, why not ask us first if we'd like to expand, before creating a fork?