First off, Kathy, I have to say this. Personally, I love the idea of sending periodic messages to past customers via the email addresses provided through PayPal. However, I was recently informed that this could be seen as spam, since the customers never explicitly consented to receiving emails from the seller beyond the original sale. By gathering up email addresses through PayPal, without telling customers that you are 'collecting' addresses, you could very quickly be reported for spam. I know, it doesn't make sense from the seller's point of view, but I do understand, as a buyer, not wanting to receive messages without actually consenting to it. Which is why, if you ARE going to collect addresses, you need to clearly specify that, and allow people the option to be removed from your list. If you want to get into email marketing, you need to create a separate mailing list where people can willingly sign up. This is something I am considering in the future....
Now that I've gotten that out, I can move on to the analytics part. If you have a premium shop, there is a way to (kind of) set up Google Analytics for your shop. The code is installed as an invisible widget. The numbers aren't accurate, but the proportions are. Also, GA gives you sources, keyword searches, and all sorts of other nifty things to consider. If you search the threads here in the hub, you should be able to find the Google Analytics workaround.
The best thing we can do to promote Zibbet and our shops here, in my personal opinion, is to give up any other selling venue, get your own url and direct it to Zibbet (if you don't have a stand-alone site already), and focus on reaching the people that have not heard of Zibbet before. I gave up my Etsy shop (100 sales in 3 years) in December 2010. I started fresh here the next month. I went premium here in July 2011. I'm currently sitting at 70 items sold and an average of 2500 views per month. About 75% of my sold items were purchased from people brand new to Zibbet who found me through Google (which tells me keywords are seriously important in being found).
It IS possible to do well here, we just have to find what works for each of us.