I have had the Entrecard Advertising button on my blog for over a month. I am very happy with it so far.
Here are my top clicks from other blogs through my advertising
Investing Adventures                   39
Capitalist Attitude                         29
TimothySykes.com                      26
A-Train Finance                            23
Forex Strategies                          23
Easy Money Saving                    16
Brown Eyed Girl And Money      12
DulceNegosyante                       11
Poly-Web                                      11
Contestu.com                              10