Asking around I have been informed (In light of the recent rights debate here.) that I do not in fact own anything, even Keen, downloaded from Steam. I am merely being allowed the privilege of running it on my computer. At any time they wish Steam may pop over and go 'Ok, hand it back, all the system backups too. Your license is revoked.'Steam and your Subscription(s) require the automatic download and installation of Software onto your computer. Valve hereby grants, and you accept, a limited, terminable, non-exclusive license and right to use the Software for your personal use in accordance with this Agreement, including the Subscription Terms. The Software is licensed, not sold. Your license confers no title or ownership in the Software. To make use of the Software, you must have a Steam Account and you may be required to be running the Steam client and maintaining a connection to the Internet.
And it happens, here's someone who was in the news a while back when Amazon decided to obliterate his account without warning, quite legally just 'cause: http://consumerist.com/2011/07/15/who-a ... n-account/
It's a sad day when you can't buy Keen anymore.