There is definitely a cottage industry of street style website, but 'London Street Fashion' is by far the best one. Not just because its London based (I am biased), but viewers can navigate their way around the tube map. Getting off at different stops, they can see the different styles of the diverse city.
For example, Shorditch is the gritty, edgy, rock and roll part of London where you will find the most stylish cool kids that live and work in London's art, music, fashion, design industries. Hackney is the place to spot more Hip Hop styles and Covent Garden is the shoppings who love quirky, stores or the tourists who dress to impress. And Portobella; they're a bit more boho.