I get all of the Etsy newsletters, and last week they sent one with info about tagging. I think that tagging my items is probably one of the hardest aspects of the listing process. You need to make sure that the tags you've chosen are the ones that people will use to find your items. But if everyone is using the same tags on their items, your item may be so far down in the search that they'll still never find it!
That's where Craftopolis comes in. I'm a sucker for numbers and Craftopolis has all of the information I need in one nifty spot. They tell me how many people have stopped by my shop, how many page view I've gotten, how many shop & item hearts, how much money I've made, and which tags were used in searches that resulted in someone seeing one of my items! Gotta love it! :)
I used to use Google Analytics, but I got frustrated because I couldn't always figure out how to find out what I wanted to know. Craftopolis is SO much easier because all the information is just laid out for you. And I simply adore the tag report feature. It's awesome to be able to see which words are effective so that I can maximize my views via Etsy searches. I'm such a geek :)
Be blessed! :)