Ok thanks AWPC!
By the way, when you say play the game on any PC with the game since it is linked to your gamertag, presumably this means you must be online to activate this feature as otherwise it sounds like potentially a problem with people abusing this feature by using 1 XB/GFW login to play on more than one machine?
Yeah you get a box up onscreen which asks you beforehand to register the game to your gamertag only and asks you to enter your serial number then if you say yes to remembering this it will always be registered to your gamertag so the only way someone can play is if you give them your gamertag credentials. If you do not agree to that then you cannot use the cloud save features or roam to another PC but you can however install the game elsewhere as many times as you like there are not limits but when you find that you want to use LIVE then it will ask you to enter the serial number until you agree to have it linked to your gamertag. Then and only then can you use all the new features like the cloud saves etc etc. However, for most of LIVE anyway you need to be online otherwise some achievements will not work at all so I should imagine most gamers will want to do this anyway. This is the only DRM most new PC games on GFWL will have as well there will be no disc checks or activation limits anymore just this 1 time only linking to your gamertag (which is optional anyway). This is all down to the game publisher as well BTW if they chose to not use this feature then it may well have the same online & diskcheck securom DRM used right now.
MS are hoping this will help reduce PC piracy by getting publishers to implement gameplay modes & services which use LIVE similar to 360 so that you want to be connected with a legitimate copy to get the full functionality. LIVE has been totally free on PC for 15 months now so no need for any Gold subscription fees either as its unlikey to ever go back as few PC gamers would pay for it (quite right!!).
Next Friday the following 3 PC's games all come out the same day and all 3 will have some if not all of these new GFWL features:
Resident Evil5: LIVE Achievements, LIVE co-op play, future DLC
Batman: AA: LIVE Achievements, future DLC
Red Faction Guerilla: LIVE Achievements, LIVE MP, All 360 DLC is also included in the PC version free of charge already.
Then in October Star Wars The Clone Wars also comes to GFWL with Achievements plus there are rumoured to be another 3-4 GFWL titles (Star Wars The Force Unleashed Sith Edition is under consideration right now) as well this year so its growing rapidly now.