Can you please split out these last two sentences into their own paragraphs and clarify them a bit more? For example:

> If RACBind() is used as an lvalue (an assignee), the named property is bound to the RACBinding provided on the right-hand side of the assignment.
>
> If RACBind() is used as an rvalue, a RACBinding is returned.

Also, we should be clear about which side takes which value initially.