[TheAceOfHearts]

I wouldn't do any i18n or l10n. It increases complexity and it's very expensive. It's also difficult to get things right unless you have someone familiarized with the target audience's culture.

Also, isn't CSS support for RTL languages kinda iffy? I've noticed that in newer versions of the spec they've begun using start/end rather than left/right, which I'm guessing is meant to help when creating bidirectional interfaces. But how well supported are these changes?

My first language is Spanish. No idea what percentage of my software supports it since I never check. I always prefer using English. Not having a Spanish option has zero impact on me.

I'd be interested in hearing arguments from the pro-i18n/l10n side. I actually have lots of questions about why certain things should be supported at all. For example, why should we support +10 different calendars instead of making everyone use ISO 8601?