I think all sites should be optimized for mobile.
Tumblr makes it easy. Add “/mobile” to any Tumblr powered url and you will see a mobile version of the site. Here’s the mobile version of my tumblelog.
Thanks to this tip from Mashable my site has now been iPhone-ized as well.
So if you visit bijansabet.com from an iPhone/iPod Touch browser you should automatically see an optimized version of the site.
It looks like this: