Lynne,
I personally don't use Plurk but I do use FB, Instagram and Flickr. My blog is also included on feeds. I think Instagram has probably noticed a surge due to the Flickr changes. All helps but you have to be vigilant in promotion especially if you're a designer trying to sell to customers. Having your own bloggers would help you too, to get the word out.
I started out using Blogger when it was called Blogspot back then. I switched to WordPress many years ago and I love it but that's just a personal user preference. I think both platforms have pluses and minuses but you could put a slurl to your store in your post and keep track of how many times it's been clicked on. You can definitely do that on WordPress.
Linda