You are not the only one. We are generating 0 ad impressions as well despite recording traffic after joining the ad revenue program.
A possible explanation may be similar to the forum login issue for new accounts. If you had Ad Revenue installed before the migration then it is working again (which is why no one has said anything yet). However if you have a new account and just signed up, its probably not working, We've had ad revenue turned on ever since it became available again about 9 days ago and the impressions constantly remain at 0. We haven't said much because we know that staff is really stretched thin right now, but maybe since others are experiencing this, it is time to say something. I'm sure on Monday staff will notice this.