I guess (I have no stats other than my experience) one of biggest reasons posts are closed as off topic (but there is another suitable SE site) is people asking for software!
We have http://softwarerecs.stackexchange.com/ as part of the SE, but this option isn't with our list of defaults.
The defaults currently are
meta.superuser.com
stackoverflow.com
serverfault.com
webapps.stackexchange.com
android.stackexchange.com
I know we can add our own reason why something should be off topic, but that is not as easy as clicking an already defined button with defined functionality!
Can this be added as an option? Or is there too much risk that most questions about software are actually too low quality?