My colleague, Peter Andrea, makes a good point:

“The truth is we already have checkboxes (and every other HTML-mandated contrivance). There are NO mainstream communication products (that I am aware of) that replicate an HTML experience without an HTML equivalent. What this boils down to is a fork in the stream. There is not one major ISP or CSP that has decided to forego the fork and forge ahead to the Webtop land of desktop equivalent interaction. Why is this? For exactly the points that Sarah makes in her entry. There are at least 15 years of precedence that need to be migrated. This does not happen overnight. That is understood, and fine… but the fall-back is readily available. Can’t hack drag and drop? Have issues w/ shift+select? Then HTML is your friend. Be there. Enjoy the mildew.”

the rest of the post is worth reading. It’s an evolution.