Well I find it interesting...
I have a set of about 11 workspaces I flit between, often I want to keep one particular tab or window open for referral later but I am busy checking through all that I keep an eye on. And of course when I switch workspaces, that site is gone...
StickyWindows is a useful little addon which adds and extends the old System 9 Finder Popup window style to OS X. You simply drag a window to either side or bottom and it transforms to a tab. Showing is better than telling in this instance, the site has a neat video displaying its use.
Well anyway as regards OW. If you drag a window to the side of the screen, it becomes a tab and when you change workspaces...it endures. So you can pop it back out again.
Which would be very useful...if it was complete. The window is often not recognised by OW, but it's there and 'referrable to..'. But links don't work and OW doesn't recognise it in the window listings until you go back to the original workspace.
However limited it is I do find it a handy thing. StickyWindows is 15.95 bucks with an occasional nag screen, and a slick product...