While researching the reduced price behind Apple's Remote Desktop -- $79.99 on the Mac App Store versus $299.99 for up to 10 seats through Apple's website -- we in the TUAW newsroom found ourselves debating the number of allowed installs.
I perused the individual license attached to the Apple Remote Desktop app on the Mac App Store, and it said the app can be installed on computers you own or control in accordance with with the Mac App Store Product Usage Rules. These rules (which weren't on Apple legal's site as of yet, but you do see them when doing your first purchase in the Mac App Store) specify that "You may download and use an application from the Mac App Store for personal, non-commercial use on any Apple-branded products running Mac OS X that you own or control."
So that shiny copy of Remote Desktop you just downloaded? It goes to any personal Mac you own. Granted, most people aren't going to own a plethora of Macs, but it's still a better deal than $299.99 just to even use the product. Same goes for Aperture, which is $79.99 on the Mac App Store, but $199.99 through the website. Commercial enterprises will still need to buy individual licenses.
It answers a concern about whether or not Apple will restrict the number of installs you can do on the Mac. Likewise, iOS apps downloaded through the iOS App Store can be installed on any Apple-branded products running iOS.