Depends on where you live, OS-wise. But, yes, /opt has mostly been settled on in the past few years for most third party applications...and it's a place where randomly named paths are not considered a faux pas. Such as, "/opt/ruby-1.9.1" and "/opt/perl5.005_04" and such, and they don't have to live in normal /usr/local/usr, /usr/local/etc, and so on, paths, which is the norm in /usr/local. One can argue all day about what makes something a "local extension to the operating system itself". Is Python a local extension to the OS itself? What if a large number of system tools use Python (as is the case on Red Hat based systems, Gentoo, and Ubuntu more with every release)? But, because the /usr/local binary directories tend to already be in the path (and before the / equivalents) installing random stuff in there is probably a horrible idea.
But, folks really ought not be encouraging this sort of thing, in general. Unless you really know you need some specific version of software, and why, you should probably be using the OS-provided packages, which are better tested (so they're generally more reliable), better supported (so you can complain to someone when you run into a problem), and more widely used (so you can find people talking about your specific version when you hit up Google for advice).
Anyway, I agree. /opt is the socially acceptable place to put random crap on a system.
But, folks really ought not be encouraging this sort of thing, in general. Unless you really know you need some specific version of software, and why, you should probably be using the OS-provided packages, which are better tested (so they're generally more reliable), better supported (so you can complain to someone when you run into a problem), and more widely used (so you can find people talking about your specific version when you hit up Google for advice).
Anyway, I agree. /opt is the socially acceptable place to put random crap on a system.