I was just clicking on a link in the sidebar when what ended up loading was a full-page of white with some ad centered on it (didn't pay attention... had some blonde woman on it with prominent breasts, but all ads seem to these days).
Over in the corner was a message that the page I actually wanted was loading, and I could click "here" (on the word) to "skip this ad".
I did.
I've never seen these here before, but despite my state of perpetual penury, if these become more common then I'll really have to do whatever it takes to get a premium membership again.