What Happened to the Internet?

Some weeks ago, I was cockily boasting about 45% of the visits to my website were over IPv6, and nudged the last 54% to join us here in the 21th century.
Then came Christmas, and the world (myself included) was off on vacation – and look what happened: IPv6 access dropped considerable, so that now only 0.58% of the visits to thomasclausen.net have been via IPv6 ;(

Drop in IPv6 access?
I have not done any detailed analysis of this just yet, but it is curious.

Access to my side (expectedly) dropped considerably over the holiday season (and picked up surprisingly strongly in the first week of January).

Week-over-week number of unique visitors to thomasclausen.net
One guess would be that the “IPv6 geeks”, who frequent the site, have IPv6 from their homes and offices (for example, native IPv6 was a deciding factor for my own choice of Free.fr as my home ISP,) – but, perhaps, not from their vacation sites, or via their mobile operator (for some reason Free.fr does not offer IPv6 on their mobile subscriptions)?

I’ll have to look into that in more details, especially to see how fast IPv6 access ramps up again. I wonder if our friends at Cisco 6Lab have any explanations?