I have 5 campaigns setup up in my account and all were doing well until recently when 2 of the campaigns stopped getting impressions all together. It has been 4 or 5 days now since they last had an impression. Why does this happen generally? Would increasing my bid help? It's really hard to tell what google thinks of a campaign on content because there is no visible quality score like on search.
you need to pull a PPR report and find out what sites your were showing up for, when those articles were published and determine the buzz factor of your theme. It may simply be that people are no longer reading articles about your themed content. Or it may be the advertisers blocked your campaign due to conflict of interest Or it may be Google shutting you off for irrelevance. If you cause google to lose money on content pages due to your irrelevant ads and lower than average CTR google is going to take measure required to keep the CPM value of that page high. Plus there are probably about 1,000 other reasons
You could just call Google and ask. But they will probably tell you that your ads are "not relevant", or something vague.
Most likely a "Google Slap" which basically means "irrelevance" for some reason or another. Try increasing the bid or change the ads to be more relevant to the keywords you are targeting... You can try to use "placement targeting" which is like content network, but you place your ads specifically on websites you personally desire, which makes it a whole lot easier to understand why something isn't working.. Bu it's most likely "paying too little" or "not getting enough clicks". - Chris
Google does not slap content campaigns... either the site owner blocks your ads or Google stops showing ads due to irrelevance. This is not considered a slap
I think it must be some sort of 'slap' because the campaigns were pretty broad and must've appeared on a lot of different sites so I doubt the reason is any sort of site block. The CTR for these 2 campaigns averaged 0.01% - pretty poor and maybe the reason why they got 'slapped'. Interestingly, the campaigns both lasted exactly the same amount of time. I started the campaigns one day apart and the impressions came to and end one day apart too.