It gets tiresome dealing with guesswork to see what OS a user may be running without actually asking them up front, especially if they didn't volunteer it outright.
Some extra not-so-anonymous analytical information gathering would be potentially useful for satisfying my curiosity about why random users are still using ancient versions of software that went out of style a decade ago.
I would usually just grep the httpd logs for their IP address, but in this case, I have a special setup:
NGinx running as apache:nginx, because I find it easier to re-own nginx than it is to constantly re-own the PHP session directory to nginx:nginx every single time I upgrade the PHP package. The side effect is that even though I am using a replacement nginx package, my distribution still insists I install the stock nginx package, which, every time it is upgraded, re-owns the /var/log/nginx directory to nginx:nginx, which then makes my logs become unwritable at the next daily rotation. As you can see, I am at odds with CentOS and the general RHEL decision to have per-httpd users like apache and nginx, instead of having simple www and/or www-data users generic to each brand of httpd. Not my decision to use CentOS, I would have gone with Ubuntu LTS.
http://www.elkarte.net/community/index.php?topic=3474.0 ?