This has been suggested before but I would like to comment as a recent topic.
I belive that w3schools has some of the best resources that I have found on the web and would love to see it as an App for my iPod - something that I could reference the syntax of HTML tags, CSS selectors, JavaScript objects, etc. while I am working without having to leave what I am doing to open my browser, locate it on the w3schools website and then compare it back and forth with what I am doing. I use other apps that serve this purpose for me to some degree but I still find myself forced to go back to w3schools.com to get better clarification. Some may argue that I could simply browse w3schools.com on my iPod touch but honestly the site is difficult to navigate and view because of the small screen size.
Please, consider this w3schools. I really like your website the best as far as a reading based school. There are others that I do like that present their materials through videos, however.
And honestly having Apps help advertise your site.