Great! Thanks for information Kevin. I'm glad you got so many sales.
The issue of which type of promotion works best is very hard to compare. Twittering may increase immediate views to a particular item, but links on various websites can increase long term views as it can help with search engine rankings such as Google, so it's kind of like comparing sausages with hosepipe. They both might be round, but they have very different uses. I think a combination of all types of promotion will increase exposure all around.
I have had favourable comments about your cards from people I told about you via email and on Facebook. They may not have purchased straight away but they are at least now aware of your shop and that they like goods within it. So when they do need cards in the future there is some chance that they will purchase some from you.
Let's hope that this works well for everyone on board. I, as someone that sells higher priced goods, probably won't gain as many sales as you did Kevin, but I'll be happy just to know a whole lot more people know my shop even exists here on Coriandr. Upping the profile of my shop here is my goal and any sales will be a great bonus
