AI've seen several tutorials on buttercream and fondant ruffles. Thought I had a pretty goig idea on what is possible from both until I saw this picture

http://www.weddingsbylilly.com/wedding-cake/buttercream-ruffle-wedding-cake/

How do you use buttercream to make ruffles this thin. Doesn't seem possible.

I think whoever wrote the blurb to that cake was mistaken, or referring to the color?  I definitely don't think its buttercream--you can see the lines of the individual strips that would be there with fondant/gum paste.
 

AThis thread talks about a cake that looks like the one that you posted.

cakecentral.com/t/756281/how-much-should-i-charge-for-the-ruffled-maggie-austin-look-cake-per-serving

AThanks for taking the time to respond. I thought it had to be fondant but as a newbie there's alot I still have to learn so I wanted to make sure.

There is no way that is buttercream.  That's 100% fondant or gumpaste.  I just posted a message to the writer of that blog telling her she's wrong and that she should correct her post.

I also noticed she has a wedding cake gallery but isn't crediting a single cake maker from the photos she is using on it.  Uncool.

This stuff makes me mad.