Using Entrecard

I just started using Entrecard yesterday and to be honest, I'm not sure exactly as to how it works. All three blogs of mine have their own Entrecard buttons, and here they are so you can see what they look like:

This one's for Something and Nothing at All.

This one's for this blog, of course.

And this one's for Keisha's blog.

I got as far as designing a button or a logo if you may, that's 125x125 pixels in size. And I've been visiting some blogs with Entrecard cards and dropping my card. I also got some ad requests and everything seems pretty cool. I am beginning to think that Entrecard's goal is for members to earn traffic as you'll be visiting other blogs to earn credits to advertise on other blogs. So it's a pretty cool thing after all.

Anyone there who's been using Entrecard? Hope you'll share some things I should know about it. Thanks in advance.