If you don't know what all Creative Commons is -- and for the longest time, I didn't -- in basic terms, it's a new level of copyright and licensing for the Internet age. Copyrights and trademarks are highly restrictive and philosophically go against what the Internet is all about. Accepting that, some people got together and made a handful of licenses with simple, visual-cue logos, that someone can glance at and understand.
Take the one on this site, for example. The (cc) part is the same on every license, so you can quickly identify it as a Creative Commons license of some kind. The BY part, "Attribution", means that while you are allowed to reproduce any article on this site, you can print it, put it on your own site, whatever - you just gotta credit me by name and include the URL back here. You don't have to ask permission to use something, which is the whole point of a Creative Commons license. If I post a recipe and you like it and want to share it, you just gotta say where you got it, even if it's a discreet note at the bottom. No further permission and no payment is required. The NC part, Non-Commercial, means you can't sell it. You can't download a bunch of articles and put it on a site people have to pay to access. Or sell them for any price. Not that someone feasibly could, the point is that if they could, they can't. And the ND part, Non-Derivative, just means you can't change it. This part's important. It means someone can't take an article I write, change what I said, and post it somewhere else. They can comment on it (e.g. to say "This is the recipe I found, blah blah blah, but I use 2 cups of this instead of 3 and I add this other ingredient", to use an example) but can't change it.
I don't even know if there's any recourse for violating a Creative Commons license. I've never heard of such a thing. I could be wrong, but it may just be an idea with no real legal backing. Probably so, but it's a good idea, and it's a cut above contacting someone and having to ask for their permission to use something you wrote/made, if you don't intend to profit from it.
As for what it means, nothing new to just read the site. And if you want to repost something, it's easier and clearer how. That's all.