I just found this nifty tool on etsy storque, which allows etsy sellers to post a free ad of their shops and items via blogs, emails, facebook etc. The article and how-to is here:
It looks quite easy to do, I will try to put mine on the left side of this blog (above my flickr photos section) but for now you can see how it looks for my handmadewithjoy etsy shop. There is a choice of 3 sizes and the one below is the big vertical one. It basically let people click on any of the images in it and buy that item directly: clicking on one item will show the description and a “buy it now” click which if you click will direct you to etsy, the item is then automatically put in a cart on etsy and from there the buyer can either remove it from the cart or click on the item to get more info about it (the item page is then fully shown there along with the seller’s shop) or click on “checkout” if they are committed to buy it.
Update: I have just learned that it is not possible to add this as a widget on a sidebar in a wordpress blog.