This site was quietly upgraded to Drupal 7, in stages over the course of the past few days. Well, I say quietly: it was pretty noticeable from my perspective. But hopefully nobody else realised that it was happening, or had suddenly switched; that was the point!
Partly in order to work out whether or not it could be done, I very purposefully did an upgrade of the old D6 site, and not a migration of the content into a new D7 site. It turns out that it could indeed be done, although I'm sure the simplicity of my site has a lot to do with that.
I'll do another blogpost in a few days, about how I accomplished it, but I'm waiting for the dust to settle, the bugs to shake out etc. Speaking of which, I'm off to check that this post appears in my RSS reader of choice!