I'm assuming the SE updater is simply that - an update for the SE content. You don't need it if you don't have it, or if you don't use the stuff. The Content Updater should be an update to ALL the content that the program includes except, of course, the SE update - why update SE content for people who don't have it anyway? Thus the Content Updater should be for everyone. I haven't been able to download it though since it's never worked when I try, but I'm just using my experience with past release.

Then, there are the Service Releases. These are supposed to target aspects of the software itself and as such, they are much more important than the Content Updaters. And if there's an SR 1.1 update, well, be glad ef is tackling the aspects of Poser that need fixing. Maybe what's fixed is something minor and thus it doesn't justify a full SR number so they added a .1.

Anyway, that's not unheard of in the software industry. I use XSI at my workplace and I recall that about 4 months after the release of XSI 3.5 they released the ill-designed XSI 3.5.1 update. That update broke a lot of render options so they had to hurriedly release an XSI 3.5.1.1 update. Pretty absurd huh? But it happens, even in the highest end segments of the market (and XSI's a heck of a piece of kit - used to be $14,995 for the Advanced package back in those days, it's around $8,000 now).