Etsy still rules as the biggest site for buying and selling crafts but as they grow, they run into a similar situation as eBay did. The larger a company becomes, the harder it is to satisfy hundreds of thousands of users. No matter what they do, they are going to have lots of unhappy members.
During my training as a guerrilla marketing coach, I learned that it’s more effective and more profitable to have as many marketing messages out there as you can.
Having multiple presences means that you increase your chances of your promotion actually getting through to your prospects. Another benefit is that you create branding / exposure, so that by the time someone comes across you on one shopping site, they may have already seen your name elsewhere.
Another advantage of being in many places online is that if one site should go out of business, delete your account, or otherwise disappear, you are diversified and can continue doing business.