It seems that Nintendo is rather busy with maintenance at the moment, with Nintendo of Europe now confirming some upcoming disruption to Club Nintendo. No specific time frames are given, just an apology for anticipated patches of downtime on 11th March; perhaps some changes are on the way to the website, or it could be behind-the-scenes work that doesn't affect the user experience.
The tweet confirming the maintenance is below, though it gives no indication of what changes (if any) are coming.
Club Nintendo has seemingly remained unchanged for a fairly lengthy period in Europe, at least, albeit with new products being added at some points. There's no indication whether Nintendo of America is lining up similar work too, though of course we have extended Nintendo Network maintenance in all territories coming on 13th March.