It seems like this "Open Source" vs. "Shared Source" thing is like other idealogical debates-- each side choses its own words to cast the debate on their terms.
For instance, "death tax" (you don't want to have to pay money to die, do you?) vs "estate tax" (you don't want families to be eternally rich without working for it, do you?)
Or "Pro-Life" vs "Pro-Choice". The pro-choicers don't want to merely say that they're on the opposite side of the debate-- then outsiders might think of them as anti-life. In fract, pro-choicers really AREN'T diametrically opposite. They pick a different continuum (choice, non-choice) to emphasize the strengths of their side.
In a way, this is what microsoft is doing. The term "Open Source" makes it seem as if corporations are 100% closed. Microsoft has made the first come-back, saying that they've been partially open for quite some time, "we're not Closed Source". But the symantic difference between "Closed Source vs Open Source" and "Shared Source vs Open Source" seems very small (or there wouldn't be a debate). Thus, the debate is still cast in OSS's terms. That is, unless Microsoft can dupe people into thinking that there is no debate-- that there is no difference between open and shared source, so there need not be another contiuum. Only Microsoft could consider such a tactic.
In which case, I don't understand why Mundie is debating on July 26th.