First off... Skidmarks are gross. I dont care if its in your pants, chair or whatever. If you have problems with Skidmarks... Get some personal Hygene advice.
Posting in the nude should not make a difference... YOU cant see me, I cant see you, so why does it matter if I am nakie...? Unless I am telling everyone... HEY I AM SO NAKED RIGHT NOW!!! In which case you would probably have issues with needing attention.
So, i guess nude posting is cool. Just like nude cooking, or watching TV, or reading your book, or sleeping in the buff for that matter. I personally have posted naked... But its not something I do on a regular basis, as it gets cold.