I am interested in technical considerations I should mind to safely switch my naked domain to a www. subdomain. By safely I mean things like not loosing SEO (redirects will suffice?) or avoiding some redirect loops (I imagine it's not hard to screw this up).
I would like to switch to a www subdomain, as I plan to scale the site up and would like to make use of cookie-less static.mydomain.com subdomain. (Yes, I know I could buy a separate domain for that, but I prefer not to.)
I am aware any cookie that has been already set on the naked domain will be sent to static.mydomain.com anyway. I'm interested in the solution nevertheless, even if only for the future users.
This question is not about DNS setup or server config, but rather general technical considerations I should care about when doing the switch.
If this helps anyone answering the question, feel free to inspect the cookies sent on the current naked domain: http://zadrutowani.pl
I'm aware it's non-SSL, I'm about to drop Wordpress altogether. Currently it's a WP on Apache, it'll be a custom solution on Nginx.