TL;DR: Birthday celebration good; Windows 10 "flavoring" bad.
As someone who's never especially enjoyed the close and snuggly relations between Super User and Microsoft - at least among some (vocal) subsets of the community - I'm against "theming" our birthday in the context of the Windows 10 release.
Look, we're not microsoft.stackexchange.com
or windows.stackexchange.com
. In practice, we get many questions that are not particular to any OS, and questions about OSes other than Windows, with as much frequency as we get questions about Microsoft products. The topicality rules allow this, so our site casts a pretty wide net. ... Actually, it's not just that the topicality rules allow questions about non-Windows OSes; it's that the topicality rules don't specifically pick out Microsoft products as being "special" or "extremely on-topic" moreso than any other OS or technology.
In short, if we're not celebrating Fedora releases or Ubuntu releases or Mac OS X releases or VMware Workstation releases or ffmpeg releases, why should we celebrate Windows releases? I think it sends the wrong message to the community and lends an undue amount of support to products of a particular company, and could potentially confuse users into thinking that we are windows.stackexchange.com
, and maybe think twice about asking a good non-Windows question here.
Considering we've never had any contests for any product releases other than Windows, it seems oddly bias to favor a Microsoft OS release as a special event. I was pretty firmly against the thing we did for Windows 8, and I feel the same way about this.
I'm all for getting Windows 10 questions asked and answered here on Super User, but I don't think we need to especially encourage it with any kind of perks or special rewards or contests to make that happen. It'll happen naturally. Our community is large enough and stable enough to be self-sustaining. We have enough askers and answerers to get it done with no marketing or promotion necessary.
Celebrating Super User's 6th anniversary would also be a very nice thing to do. I'm not sure in what way we should celebrate, and how that should affect the site (should we have a contest? special features for a limited time? I don't know), but whatever you guys come up with will probably be fine by me. As long as it doesn't have a big Windows logo attached to it.