That seems fair, then. If, as an advertiser, you are charged per impression, and you receive no impressions, the advertiser is not charged. Also, can any HN A

That seems fair, then. If, as an advertiser, you are charged per impression, and you receive no impressions, the advertiser is not charged. Also, can any HN Adwords users comment on their experiences using Adwords to advertise to Gmail in terms of effectiveness? It seems to me that a large portion of the ads (gmail) are from unsophisticated Adwords advertisers that have not configured their campaigns properly.