Amazon may not be going away tomorrow, but they have form for disallowing redownloads of old ebook purchases. If you dared to buy ebooks from them pre-Kindle, you can't access them anymore. If you hold onto your Kindle devices for too long instead of replacing them with a newer model, you can't access your old books that aren't already downloaded until you buy a new device.
For now, Sony has no issues with people redownloading PS3 games. Or PSP games onto a Vita - not sure if you can still download onto an original PSP. They'll probably jump on the Amazon revoke-download train eventually, though.
For now, Sony has no issues with people redownloading PS3 games. Or PSP games onto a Vita - not sure if you can still download onto an original PSP. They'll probably jump on the Amazon revoke-download train eventually, though.