How ads show on videos you monetize
When you enable your channel for monetization, you can turn on ads for your videos. Ads are served through the AdSense auction, DoubleClick, and other YouTube-sold sources. Once you turn on monetization, it may take some time for ads to appear.
The ads displayed on your video are automatically determined based on contextual factors, including (but not limited to) your video metadata and whether the content is advertiser-friendly.
We regularly monitor and update our systems to deliver the most relevant ads to your videos. However, we don't manually control all of the ads that appear with your videos, so we can't guarantee that specific ads will be displayed.
Ads will not always appear on videos enabled for monetization. There may not always be an ad available at the time of viewing. If you think there's a problem with ads, learn why ads might not be showing on your videos.
What are partner-sold ads?
Since 2010, YouTube has allowed a small number of partners to sell ads for the content they place on YouTube. These ads are called "partner-sold ads." In order to qualify for partner-sold ads, organizations must distribute content across multiple platforms and have the company infrastructure (including sales forces) to sell ads against their own videos.
For partner-sold ads, the partners work directly with advertisers to serve ads on content they own. Advertisers purchase ads from these partners so that the ads show up on specific content. This means that partner-sold ads may show even on videos that YouTube considers "not suitable for most advertisers." This is because these partners take full responsibility for the ad placement by working directly with the advertisers; they bear the full risk of putting ads on content advertisers may not think is brand suitable.
Partners cannot sell ads against content that is related to tragedies.