XCDP IconThe gamercards we link to on this blog come from work done by Jason Young, from MyGamerCard.net (get your own!).  He's part of the Xbox Community Developer program.  K1lla did a quick interivew that I found interesting.  Here's a snip:

MyGamerCard.net is a service that provides an easier way to display your Xbox LIVE GamerCard. Instructions for Microsoft's official card include the usage of an 'iframe', which is an HTML tag that many sites prohibit.
What MGC does is take the information contained on that card and create a
dynamically-generated image that looks exactly like the 'official' card.