Current employer and client. I'm their sole Web Designer, Developer and e-Marketer. It's plenty to handle for one person, but can claim the website's success to be a direct correlation of my contributions. Starting in late August of last year, I spent the latter of 2014 migrating QDL's inventory from the now defunct Prostores, redesigning/rebranding and developing their website on Shopify. Only 24 weeks since the new launch in late January, sales at Quality Discount Lighting has risen 60% from its previous years. And it's never, ever had this type of success in its 7 years of existence online.
More thoughts can be found in a side blog that I've maintained on Tumblr, mainly as a way to see if others need assistance with the Ruby-based Shopify framework. Prior to QDL, I had never tried it, but was good to explore after studying Ruby and web frameworks such as Sinatra and Rails during camp. Most of the development work was done on the front end, and at times, became somewhat of a mess. See Tumblr blog for samples. Regardless, this was overall good practice – along with using design principles and integrating responsive design to take care of our visitors' wide range of devices.
Much of what you do on Shopify is develop a theme and use the software itself, kind of like WordPress. And similarly, it was specifically constructed for client needs and use. Starting with something prebuilt is often a good way to get a jump start, which is what I've had to do, but more for its barebone structure and functionality. Unfortunately, anything prebuilt only blankets generic features, usually lacking, so a customer login was designed and developed separately; integrating things like order information and history.
In recent months, I've been monitoring analytics and establishing SEO keywords, the latter for which I've had to conduct research and technically rework finalized templates. Running Google campaigns on AdWords seems to be more trial and error than anything else, but only after getting a good handle for the system. It takes some knowledge of what's what, and small organizations tend to emphasize the bottom line. Social Media channels have also started or restarted under my direction, which have yielded some traffic and sales at this point. It's really hard to argue free marketing.
See Quality Discount Lighting.