About half the participants had trouble with properties being URLs --
they started trying to use them as values. For example this:
   <span itemprop="http://flickr.com/camera/">Digital Rebel</span>
...was sometimes interpreted as meaning that the link
"http://flickr.com/camera/" contains information about the Digital
Rebel camera.

Containership was missed by everyone. People simply added itemprop=""s
everywhere and didn't bother with wrapping them in <div itemscope>s.

People made up itemprop="" property names all the time, though some at
least tried to copy from examples. Few read the spec's list of
keywords, fewer still made use of the list.

item="" confused everyone. itemscope="" helped at least one person
understand the scoping aspect. itemtype="" helped people understand
that it's a type.

itemprop="about" confused people because of the keyword
"about". "itemid" wasn't as confusing. The entire concept of naming
the item was rather missed by people though. Nobody got it when the
attribute was named item="".



Proposal:
* have itemscope="" to declare a new scope
* have itemtype="" to declare the types
* have itemprop="itemid" instead of "about"
* have <itemref ref=""> instead of itemfor=""