Marcus Ash, a Windows Phone Group Program Manager, discussed the idea at the SMX Advanced conference in Seattle. The company wants Cortana to be 'pervasive' not just at a country/geographic level but at a tech level across different devices and perhaps different platforms.
We want to scale Cortana internationally and across devices. The Android/iOS question is interesting. We’re asking, would Cortana be as effective if she didn’t have access to the details on your phone? We’re still trying to get Cortana adopted on Windows Phone and figure out what it wants to become there. But we’re actively talking about this.
I think it’s natural to think that an assistant that only runs on one device … the idea that she will be very pervasive is important to us.
Microsoft also hinted that Cortana could arrive on desktops, vehicles, and other venues.
When discussing the impact of Cortana, Ash said he didn't think Cortana would mean the death of the search box.
“I can’t imagine that,” Ash said. “The search box is what people know. That’s why we’re trying to bring [it and Cortana] together. The declarative intent of traditional search saves us so much effort — if you tell us what your interest are via search, Cortana gets so much better. We think Cortana makes you more likely to search, it doesn’t replace search.”