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Sure, if you use the site artisteem to make your post you need to add these tags, CR is for a unique creation, CO is for contest etc. I will actually be making a post about it this week, that is why I tried it out first!

so, this is the meaning :D
Thank you for hte fast explanation! looking forward to your post on this subject :)

No problem, thats why I am making a post I found it a bit confusing too :D