I run a few websites/blogs on WordPress, one of which is monetised.

The number of impressions/views/however you wanna call it is stable, roughly the same, but the number of ads being showed to viewers (or served to viewers, as WP put it) has gone down significantly. Most days it's zero.

So I got in touch with WP and they've explained that other users reported this. Apparently, it's due to the fact that WordPress is migrating to a new partner, and apparently there's a technical glitch, and apparently they're not sure whether that's on WP's part or the partner(s)' part.

Either way, I was told it's temporary, and I was told it should be fixed in the next few days and weeks.

I hope so.

I'll keep you posted.