Time to start your A/B Testing! Google finally realizes that the standard square corners on AdSense ads don’t fit in with every website and theme. Most prefer not to use borders at all (including myself,) allowing the ads to blend in better with the website design, but i really like the look of these corners now.

Here is an example of a 468×60 banner with “Very rounded corners:”

If that doesn’t show anything, try refreshing until it does. The ad could look a little bit better, it looks like the leftmost text is running into the border a little bit. It still looks better than the normal square corners, but will it convert better than ads with no border?

I’m going to make 50% of my ads with no border, and 50% with rounded corners and see which one converts better. You should do the same; A/B Testing is one of the best ways to ensure you’re getting the most out of your ad space. I’ll write a comprehensive tutorial on A/B Testing in the future.

You can also vary the amount of roundness of your corners. When you choose your borders, AdSense provides you with a choice of either square corners, slightly rounded corners, and very rounded corners. The code comes out like this:

google_ui_features = “rc:10″; for very rounded corners
google_ui_features = “rc:6″; for slightly rounded corners
google_ui_features = “rc:0″; square corners

From my quick testing, it doesn’t seem like you can edit the number for custom-rounded corners. In other words, you can’t enter “rc:8″ in place of “rc:10″ to get “mostly rounded corners.” If I’m mistaken on this, please let me know, but it didn’t work for me.

source: QuickOnlineTips