Part of the interesting stuff of Entrecard is the ability to advertise on other blogs. You can advertise at other blogs to bring traffic to your blog. Just make sure that you have enough Entrecard credit to purchase Ads space from that blog.
Above are the clicks from the blog that you advertised. Use your Entrecard credit wisely. Advertise on the blog that will bring traffic to you only. But how are you going to know before you advertise?
Top advert clicks
Above is the most advert click for the last 30 days. You can track your ads performance based on this chart. It will help to determine which blog that actually brings traffic to you. However, not all the higher clicks are worth the price.
Credits per click
Above chart displays credits per click for the ads that you purchased. The lowest credit == the better. You spend less on the Entrecard credit to bring more traffic.
Finally, plan well to get more traffic with less Entrecard credit.