John's just guessing (as we've all been doing) about it relying on PPS. Nothing has been announced anywhere yet.
You can, however, see early signs of some clipboard support in the browser. If you visit a page with text, and click-and-hold for about 2s, you'll see a chunk of text selected and two funny looking "thumb" widgets show up. They don't really work, and are misplaced, but the idea would be that you can drag them around to adjust the selection, then -- presumably -- make some other gesture to trigger a copy/cut operation. (Or maybe there will be a popup menu.)
There's also a shared folder along with the videos/, photos/, etc called "shared/clipboard", so we have numerous indications there will be some sort of cut/paste support in future, and maybe at launch.
