Actually, I'm not so much interesting on WHERE you online shop, but how do you go about finding new stores? Google? Forums like this? Word of mouth? Blogs? eBay?
Many contact me. I am a fashion writer. However, I surf or word of mouth. I agree that you need to sift through a lot of internet stuff, but when I am on a trail for a new store I stick to it. I hope this helps.
I peek on "missyconfidential" as well for recent updates.
Vogue Australia forums have a huge range of stores and online discount codes for orders as well as tip-offs for upcoming sales.