I am currently building a website for the clan I belong to.
A few features that would be extremely useful to help any web developers with clan sites would be:
A (rss) feed to display of the latest official COD news. Up and coming releases of maps, double xp weekends, patch releases etc etc
The ability to embed either a general clan ops / challenges calendar on a website or clan specific one or even subscribe to the calendar through another calendar service. At minimum a rss feed to show this information.
A feed showing clan notifications to place on site.
A quick look clan stats display.
A web developers kit with some free to use images (prestige emblems, create a class content, scorestreak icons)