A lot of publishers that use Adsense will see that they gain traffic from different Adsense products being:
Adsense for Content
This is the most common product used by publishers. This is the traffic gained by adverts that are on publisher’s websites. They are the typical Adsense adverts seen on websites. If you have a high traffic website, the page views for this product will be high. Adsense for Content usually has the lowest CTR out of the three above products.
Adsense for Search
Adsense for Search is the product for adverts which are displayed on search pages. For publishers that use Adsense for Search, they will have a custom search engine by Google on their website. When the search results appear, adverts will be displayed on them. Adsense for Search adverts are these adverts. Their CTR is good but is only really effective if the adverts get lots of traffic (lots of people use the search bar).
Adsense for Content Host
This product is a bit of a mystery to most publishers because it has a similar name to Adsense for Content. Don’t be thrown by this because they are unrelated. Adsense for Content Host is the name given to adverts that appear on videos being mainly YouTube. When you watch YouTube videos, you will sometimes get adverts popping up at the bottom of the video or in the right sidebar. These are them adverts. Adsense for Content Host has the stereotype for gaining the highest CTR (of around 15% in some cases). However, the low CPC lets it down.
If you are gaining traffic from different products that you do not use, do not worry. You won’t get banned because it is a mistake by Google and not you. You may also find that if you do have a YouTube account which you have not used in ages, Google may have in that time given the account the ability to show adverts (if it gets enough traffic). Therefore, don’t be surprised if you see different products appear on your Google Adsense homepage.