So perhaps if you are around that level of clicks or impressions you may be caught in a review period, where an aditor is looking at your account.
One of my campaign suddenly stop showing. No impression being serve since yesterday. Is this something to do with the recent changes in the adword program?
I'd almost guarantee that there is no connection. As an aside, over the years I've found that when any change occurs in the AdWords system, we'll get a long flurry of emails which pin an amazing variety of unrelated 'issues' on the change, whatever it happens to be. Usually, the reasons behind the issue turn out to be much less exotic.
I've already contacted google and awaiting for a reply.
This is the best plan, of course, as support can look at the account and will usually be able to pinpoint the issue in short order. In the meantime, here are some of the most common reasons for no impressions all of a sudden:
* Campaign had an end-date set, which has now passed
* Campaign was mistakenly paused
* Ad was mistakenly deleted, so there is no ad to show
* Maximum CPC has been set higher (or equal to) Daily Budget
* Keywords are disabled or on-hold
* Keywords were changed to ones which are of a sensitive nature, and must be approved before running, even on Google.
These are off the top of my head, and I'll bet I'm missing a few - and I hope that you'll hear from AdWords support soon, and get things squared away.
AWA
Google explained that this is to make sure that there is distribution throughout the day. I now set allowance at 2x expected expense - almost cost me my job.