I have a 2010 iMac running 10.6.8, and an 18 month old Macbook Air that came with 10.7 Lion. I was ready to try Lion on my iMac (despite problems it may create with my pro software) but I was unable to access it in the app store, only 10.8 Mountain Lion (which I'm sure will prevent all working due to program incompatibilities). My local Apple store told me there should be a USB in the Air box with the OS on it; apparently my Air was just before the very narrow window when Apple was including USB drives, before they decided that only a computer bought with an OS could be used with that OS. They went on to create the recovery assistant, which just further limits the use of an OS someone owns. (I tried to install 10.7 on my iMac using the recovery assistant, but it refused.) There is a strong chance Lion won't be compatible with many programs I use, and if I were to buy a second license from the app store, I'm absolutely certain I wouldn't be allowed to return it. Buy once and use on all your computers? Biggest scam ever, because no matter what, you must specifically pay for an update once - buying a computer with the new OS doesn't count. So how can I pull Lion off of my Air to test it with my iMac, without buying what I already own and potentially adding the additional aggravation of trying to return software due to massive program incompatibilities?