Pat Thyself Firmly on the Back

If you want to tag a business website as amateur, look for the section about how hard they worked on it.

Somewhere on the site, they wax eloquent about the thousands of hours they've put into spittin' and polishin', shinin' and prettifyin' just so that 'your visit and experience at La De Freakin' Dah Company LLC will be the best possible ever.' They'll probably go on and on and on about the massive investment of cost and time and dedication and resources and the latest technology that they have lovingly poured into this venture.

Of course they worked hard on it. If they didn't work hard on it, it wouldn't be much, would it?