Originally Posted by happycheapskate
I politely disagree. The derailleurs with integral hangers brace against the dropout nicely, and the anti-rotation pin can couple with a top-hat nut (usually come with them) or conventional nut and washer, behind the dropout. You do not have to drill a hole in the dropout for the anti-rotation pin. If you have a good eye and steady hand, you can weld a hanger tab on any standard dropout. I put one on a BMX when I was a kid, and made a 7speed BMX chopper that worked nicely.
Only generic multispeed bikes use that method, always with generic derailleurs, too. The bike you linked to is a generic as well. Bikes properly designed for derailleurs have the right provisions from the get-go.
One of these will work with proper derailleurs on generic bikes, tho: