[Audentio]

Originally Posted by Marco van Herwaarden

Unless i am mistaken, it seems that the original license only allow the use if your website is giving the credits to the original author. So each board using these should have a link back to the original website.

I read the license last month and I'm pretty sure that he encourages use of the icons. Notice how he would like to be emailed to see how they are being used.

?Do the Flag/Mini icons sets need attribution or a link? (the answer is no ? both sets are public domain)

Exact license:

I also love to hear of my work being used, feel encouraged to send an email with a link or screenshot of the icons in their new home to mjames at gmail dot com. This work is licensed under a Creative Commons Attribution 2.5 License. This means you may use it for any purpose, and make any changes you like. All I ask is that you include a link back to this page in your credits (although a giant link on every page of your website really isn't needed, contact me to discuss specifics).

It seems to imply that a link would be nice, but he does say "any" purpose. I do not count myself as owner of these buttons, just organizer meaning I added a blue background, named the slices, and shove em in a psd.

By all means, if you want to include a link back to his site, thats not my choice, but I certainly don't think its required.