We still get a fair number of people posting things on the wrong site. This is largely because they think their distribution is a derivative or is somehow related to Ubuntu and that makes this the right site. Others seem to drift in off the back of other questions they find through Google.
Either way, the current way of handling these (letting them post and closing their question with a snotty close message) is a huge waste of everybody's time.
Could we include something like the following that alerts these users that their distribution may not be supported on the site? I'm talking about a message like this:
Ask Ubuntu is a site for users of Ubuntu Linux distribution and its official derivatives (learn more). You appear not to be using one of these. Posts here may not apply to you and we request you not ask questions that aren't about Ubuntu or its derivatives here, rather that you use Unix & Linux.
The message might need tuning but this is dead simple to drop into the site template without requiring any server-side code:
$().ready(function() {
if (navigator.userAgent.indexOf("buntu") == -1)
$('<div id="system-message" style="margin-top:15px">\
Ask Ubuntu is a site for users of Ubuntu Linux distribution and its \
<em>official</em> derivatives \
(<a href="https://askubuntu.com/help/on-topic">learn more</a>). \
<strong>You appear not to be using one of these</strong>. Posts here \
may not apply to you and we request you not ask questions that aren\'t \
about Ubuntu or its derivatives here, rather that you use \
<a href="http://unix.stackexchange.com">Unix & Linux</a>.\
</div>').insertAfter('#header');
});
It's important to note that this wouldn't prevent people from posting, just make them aware that they might be on the wrong site.