I see that the old Gears of War 1 game has still not made its way to Steam after all this time. 
However, its a Games for Windows Live game and it is still available 2nd hand on eBay. It is also available to download from Live Marketplace for £14.99
I was under the impression that GFWL is the same as Steam in that once a game serial number has been used, it cannot be reused or transferred.
So, Im wondering is this correct?
If so, I think all the ones on eBay will be 'offline only'

However, its a Games for Windows Live game and it is still available 2nd hand on eBay. It is also available to download from Live Marketplace for £14.99
I was under the impression that GFWL is the same as Steam in that once a game serial number has been used, it cannot be reused or transferred.
So, Im wondering is this correct?
If so, I think all the ones on eBay will be 'offline only'