Some commercial games on Desura and on Steam used Adobe Air, that I recall. But Adobe Air was installed by Desura and Steam for me, so no need to install it manually.
I don't think there is any longer term use in installing Adobe Air. It was discontinued for Linux after version 2.6, in February 2011 (which this article linked to lets you install). Current version is 3.8, released last month. I don't think any currently developed Adobe Air things will work flawlessly with the older version.