For reasons that are presently unclear, some recent connections to this blog from mobile devices were hijacked by intervening ads.
No one was more surprised by this than me, as I have not authorised any ads on this site.
This seem to have been an unintended result of one of Google's templates for mobile devices. (There's nothing in Google's documentation about this.)
The idea was that if a mobile device was detected, the blog posts would be presented in a format that was easier to read on a mobile device.
Until there's a solution, I have switched off the alternative template. Accessing the blog from a mobile device simply returns the regular site.
My apologies for any inconvenience.