If you don't, you should. Here's why:
The owners of Craftcult are super nice. AND, they're etsy sellers themselves.
Craftcult is full of seller-friendly features, such as:
Enter your username here to find out how many shop hearts and/or item hearts you have. They are even nice enough to tell you the date and TIME you received each and every bit of love. See how many item views you've got. Check if you're featured on the front page, in the storque, or in a gift guide.
This feature is soooo cool. View by date, or search specifically for any etsy member. If you're in or have been in a front page treasury, it will show up here. Trust me, it works. So far, it's informed me that "no lists were found with madbird featured. Try another search already, you pest!" Sadly, it's correct. I keep trying though.
Oh yeah, it works. Sometimes, paid advertising is a good thing. I only paid $15 for four days. The first day of my advertisement, I got a $60 sale directly from Craftcult. How do I know? Because she told me Craftcult sent her, that's how. This was my second time advertising with them. I did so well the last time I bought a 4-day ad, it took a lot of restraint to wait a few weeks before buying more time. My goal is to advertise one spot monthly. It's a good deal - give it a shot.
Even if you're not keen on buying an ad spot - if you haven't checked out the heart-o-matic, you're missing out. But be warned, it can be addicting!