Here is a screenshot of the widget:
On the true widget, the E takes you to the Entrecard website. You click on Drop yours to leave your card, then you visit the hosted blog that is displayed.
You receive Entrecard credits each time someone drops a card and each time someone clicks from your widget to your guest's blog. If you drop a card, your card goes into the blog owner's inbox at the Entrecard website in an attempt to get regular visitors.
The problem is that every marketer came out with a system to drop cards faster and blogged about it. Next, someone had to make a entrecard surfer, viewer and rotater. Now, instead of readers, you get people passing through.
I have never seen so many contests as I have since I started using entrecard. Everyone want you to subscribe to their feed, write a blogpost about their contest, fave them to Technorati, Stumble, Digg and do other things to them. It is like "Quick, grab 'em!"
If you are looking for visitors and you have the content to hold them, entrecard is a good deal. If you are trying to gain exposure for a new blog, it is worth a try. Check it out and make your own decision. Drop by Texas RV Travel blog and drop me a card. I return visits and I leave comments.