But those of us who live in Europe sometimes get absolutely infuriated by US-based startups who go for years ignoring potential non-US customers. I'm sure Fab.com would have eventually rolled out to Europe, but in the meantime I'm happy that someone else built a product that solves the same problem.
Sometimes this is a real regulatory problem, like anything to do with banking/payments/etc. But oftentimes it's just because businesses don't seem to like taking on the extra work/complexity of thinking internationally.
So while I don't like their pure copycat methods (down to page layouts), I think they're serving a valuable purpose in the marketplace.